mb/google/skryim: Add RECOVERY_MRC_CACHE FMAP section

Enable HAS_RECOVERY_MRC_CACHE config and add RECOVERY_MRC_CACHE FMAP
section to cache the MRC training data in recovery mode.

BUG=b:270569389
TEST=Build and boot to OS in Skyrim. Ensure that the Type 0x63 BIOS
directory entry is populated with the appropriate MRC_CACHE FMAP
section.

Change-Id: I3f0f41c20b61c96473e887521f84f3ad240adc2b
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73250
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>

src/mainboard/google/skyrim/Kconfig

@@ -36,6 +36,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select FW_CONFIG
 	select FW_CONFIG_SOURCE_CHROMEEC_CBI
 	select GOOGLE_SMBIOS_MAINBOARD_VERSION
+	select HAS_RECOVERY_MRC_CACHE
 	select I2C_TPM
 	select MAINBOARD_HAS_CHROMEOS
 	select MAINBOARD_HAS_TPM2

src/mainboard/google/skyrim/chromeos.fmd

@@ -22,6 +22,7 @@ FLASH@0xFF000000 16M {
 		RW_NVRAM(PRESERVE) 20K
 		SMMSTORE(PRESERVE)@0x630000 64K
 		RW_VBIOS_CACHE 64K
+		RECOVERY_MRC_CACHE(PRESERVE) 120K
 		RW_LEGACY(CBFS)
 		WP_RO@8M 8M {
 			RO_VPD(PRESERVE) 16K