ACPI: Enable FPDT on arm64

FPDT provides some boot timing records useful for analyzing
parts of the UEFI boot stack. Given the existing code works
on arm64, and allows reading the values without utilizing
/dev/mem it seems like a good idea to turn it on.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20221109174720.203723-1-jeremy.linton@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Documentation/arm64/acpi_object_usage.rst

@@ -163,7 +163,7 @@ FPDT   Section 5.2.23 (signature == "FPDT")
 
        **Firmware Performance Data Table**
 
-       Optional, not currently supported.
+       Optional, useful for boot performance profiling.
 
 GTDT   Section 5.2.24 (signature == "GTDT")
 

drivers/acpi/Kconfig

@@ -90,7 +90,7 @@ config ACPI_SPCR_TABLE
 
 config ACPI_FPDT
 	bool "ACPI Firmware Performance Data Table (FPDT) support"
-	depends on X86_64
+	depends on X86_64 || ARM64
 	help
 	  Enable support for the Firmware Performance Data Table (FPDT).
 	  This table provides information on the timing of the system