platform/x86: BIOS SAR driver for Intel M.2 Modem

Dynamic BIOS SAR driver exposing dynamic SAR information from BIOS

The Dynamic SAR (Specific Absorption Rate) driver uses ACPI DSM
(Device Specific Method) to communicate with BIOS and retrieve
dynamic SAR information and change notifications. The driver uses
sysfs to expose this data to userspace via read and notify.

Sysfs interface is documented in detail under:
Documentation/ABI/testing/sysfs-driver-intc_sar

Signed-off-by: Shravan S <s.shravan@intel.com>
Link: https://lore.kernel.org/r/20210723211452.27995-2-s.shravan@intel.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>