Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Extend idle support for newer Book-E cores.

Newer Book-E cores (e500mc, e5500, e6500) do not support the WE bit in the MSR,
and instead delegate CPU idling to the SoC.

Perhaps in the future the QORIQ_DPAA option for the mpc85xx platform will become
a subclass, which will eliminate most of the #ifdef's.

Unbreak non-SMP builds. This was broken by r259284. Also, reorganize the
code introduced in that revision a bit.

Reviewed by: nwhitehorn
MFC after: 3 weeks

Rearchitect platform memory map parsing to make it less
Open Firmware-centric:
- Keep the static list of regions in platform.c instead of ofw_machdep.c
- Move various merging and sorting operations to platform.c as well
- Move apple_hacks code out of ofw_machdep.c and into platform_powermac.c,
where it belongs
- Move CHRP-specific dynamic-reconfiguration memory parsing into
platform_chrp.c instead of pretending it is shared code

Add hook called when every new processor is brought online -- including the
BSP -- so that platform modules have a chance to add the new CPU to any
internal bookkeeping.

Approved by: re (kib)

Add some platform KOBJ extensions and continue integrating PowerPC
hypervisor infrastructure support:
- Fix coexistence of multiple platform modules in the same kernel
- Allow platform modules to provide an SMP topology
- PowerPC hypervisors limit the amount of memory accessible in real mode.
Allow the platform modules to specify the maximum real-mode address,
and modify the bits of the kernel that need to allocate
real-mode-accessible buffers to respect this limits.

Restructure how reset and poweroff are handled on PowerPC systems, since
the existing code was very platform specific, and broken for SMP systems
trying to reboot from KDB.

- Add a new PLATFORM_RESET() method to the platform KOBJ interface, and
migrate existing reset functions into platform modules.
- Modify the OF_reboot() routine to submit the request by hand to avoid
the IPIs involved in the regular openfirmware() routine. This fixes
reboot from KDB on SMP machines.
- Move non-KDB reset and poweroff functions on the Powermac platform
into the relevant power control drivers (cuda, pmu, smu), instead of
using them through the Open Firmware backdoor.
- Rename platform_chrp to platform_powermac since it has become
increasingly Powermac specific. When we gain support for IBM systems,
we will grow a new platform_chrp.

Factor out platform dependent things unrelated to device drivers into a
new platform module. These are probed in early boot, and have the
responsibility of determining the layout of physical memory, determining
the CPU timebase frequency, and handling the zoo of SMP mechanisms
found on PowerPC.

Reviewed by: marcel, raj
Book-E parts by: raj