soc/qualcomm/x1p42100: Select ARM64_USE_ARM_TRUSTED_FIRMWARE

This commit enables `ARM64_USE_ARM_TRUSTED_FIRMWARE` for the
Qualcomm X1P42100 SoC.

Selecting this option ensures that coreboot is configured to
integrate with ARM Trusted Firmware (TF-A), which is essential
for proper boot and power management functionality on this platform.

BUG=b:424149462
TEST=Able to build google/bluey.

Change-Id: I30bc3eb9eedcaaef67cccf8c2f29c6ed76c71e9a
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88251
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Pranava Y N <pranavayn@google.com>
Reviewed-by: Dinesh Gehlot <digehlot@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>

src/soc/qualcomm/x1p42100/Kconfig

@@ -8,6 +8,7 @@ config SOC_QUALCOMM_X1P42100
 	select ARCH_ROMSTAGE_ARMV8_64
 	select ARCH_VERSTAGE_ARMV8_64
 	select ARM64_USE_ARCH_TIMER
+	select ARM64_USE_ARM_TRUSTED_FIRMWARE
 	select CACHE_MRC_SETTINGS
 	select COMMONLIB_STORAGE
 	select COMMONLIB_STORAGE_SD