ACPI: Kconfig: Provide help text for the ACPI_PRMT option

mainline inclusion
from mainline-v5.14
commit 9b52363b
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I6HNB8


CVE: N/A

Intel-SIG: commit 9b52363b ACPI: Kconfig: Provide help text
for the ACPI_PRMT option.
ACPI Platform Runtime Mechanism feature backport.

--------------------------------

Add missing help text for CONFIG_ACPI_PRMT.

Fixes: cefc7ca4 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>