kernel: Drop non-standard GNU inline assignment syntax

* We needed this previously due to our gcc2 compiled kernel.
* Now that our kernel is always latest gcc, we can move to the
c++20 syntax for inline assignment.
* Improves compatibility with clang, less GNU-specific stuff

Change-Id: Ib7272a0a52554a31e9a0e788fd3f031db9049795
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5898
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

Replace B_MAX_CPU_COUNT with SMP_MAX_CPUS

Change-Id: I55c53ab35e9645e20466b09407a251571c589958
Reviewed-on: https://review.haiku-os.org/447
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

Free ci on error

acpi_cpuidle: Fix driver initialization

* For some reason the code in acpi_processor_init() assumed that the
CPU index returned by ACPI was 1-based. On my machines it is 0-based
and the syslogs on Trac from the last months don't show any
exception. The code even contained a hack to force satisifying that
assumption for a single-CPU machine.
* Instead of calling intel_cpuidle_init()/acpi_cpuidle_init() when
initializing the driver for the device node for CPU 0 -- thus
depending on the order the device manager iterates through the CPU
device nodes -- rather check whether all CPU nodes have indeed been
encountered.
* acpi_cpuidle_init_driver(): Don't leak the cookie in error case.
* acpi_cpuidle_uninit_driver(): Clear the sAcpiProcessor element for
the uninitialized CPU node. We'd also have to unregister the idle
callback when acpi_cpuidle_uninit_driver() is called for the first
CPU device node, but there isn't any API for it ATM.

Fixes a crash on machines with multiple CPUs where acpi_cpuidle_setup()
wouldn't already fail early (apparently only mine).

acpi_cpuidle.cpp: Some style cleanup

Just what I spotted at the first glance. There's more general cleanup
to be done, e.g. regarding the public API.

x86_cpuidle: use module_dependencies rather than get_module()

Signed-off-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>

cpuidle: implement acpi cpuidle driver

we prefer intel native cpuidle driver on newer intel platforms --
sandybridge or later. we'll fall back to acpi cpuidle driver for other
platforms.

Signed-off-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>

cpuidle: move generic cpuidle to generic

After this change, low level cpuidle drivers load the generic cpuidle
module if they can support the underlying platform.

change the intel cpuidle driver accordingly, now it's loaded by acpi
bus manager during boot, although it doesn't depend on acpi

Signed-off-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>

acpi_cpuidle: Fix driver initialization

* For some reason the code in acpi_processor_init() assumed that the
CPU index returned by ACPI was 1-based. On my machines it is 0-based
and the syslogs on Trac from the last months don't show any
exception. The code even contained a hack to force satisifying that
assumption for a single-CPU machine.
* Instead of calling intel_cpuidle_init()/acpi_cpuidle_init() when
initializing the driver for the device node for CPU 0 -- thus
depending on the order the device manager iterates through the CPU
device nodes -- rather check whether all CPU nodes have indeed been
encountered.
* acpi_cpuidle_init_driver(): Don't leak the cookie in error case.
* acpi_cpuidle_uninit_driver(): Clear the sAcpiProcessor element for
the uninitialized CPU node. We'd also have to unregister the idle
callback when acpi_cpuidle_uninit_driver() is called for the first
CPU device node, but there isn't any API for it ATM.

Fixes a crash on machines with multiple CPUs where acpi_cpuidle_setup()
wouldn't already fail early (apparently only mine).

acpi_cpuidle.cpp: Some style cleanup

Just what I spotted at the first glance. There's more general cleanup
to be done, e.g. regarding the public API.

x86_cpuidle: use module_dependencies rather than get_module()

Signed-off-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>

cpuidle: implement acpi cpuidle driver

we prefer intel native cpuidle driver on newer intel platforms --
sandybridge or later. we'll fall back to acpi cpuidle driver for other
platforms.

Signed-off-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>

cpuidle: move generic cpuidle to generic

After this change, low level cpuidle drivers load the generic cpuidle
module if they can support the underlying platform.

change the intel cpuidle driver accordingly, now it's loaded by acpi
bus manager during boot, although it doesn't depend on acpi

Signed-off-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>