ACPI: Introduce Platform Firmware Runtime Telemetry driver

This driver allows user space to fetch telemetry data from the
firmware with the help of the Platform Firmware Runtime Telemetry
interface.

Both PFRU and PFRT are based on ACPI _DSM interfaces located under
special device objects in the ACPI Namespace, but these interfaces
are different from each other, so it is better to provide a separate
driver from each of them, even though they share some common
definitions and naming conventions.

Tested-by: Hongyu Ning <hongyu.ning@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: Introduce Platform Firmware Runtime Update device driver

Introduce the pfr_update driver which can be used for Platform Firmware
Runtime code injection and driver update [1].

The user is expected to provide the EFI capsule, and pass it to the
driver by writing the capsule to a device special file. The capsule
is transferred by the driver to the platform firmware with the help
of an ACPI _DSM method under the special ACPI Platform Firmware
Runtime Update device (INTC1080), and the actual firmware update is
carried out by the low-level Management Mode code in the platform
firmware.

This change allows certain pieces of the platform firmware to be
updated on the fly while the system is running (runtime) without the
need to restart it, which is key in the cases when the system needs to
be available 100% of the time and it cannot afford the downtime related
to restarting it, or when the work carried out by the system is
particularly important, so it cannot be interrupted, and it is not
practical to wait until it is complete.

Link: https://uefi.org/sites/default/files/resources/Intel_MM_OS_Interface_Spec_Rev100.pdf # [1]
Tested-by: Hongyu Ning <hongyu.ning@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>