soc/mediatek/mt8192: enable CONFIG_ARM64_USE_ARM_TRUSTED_FIRMWARE

BRANCH=none
BUG=b:159079785
TEST=1. Checkout https://review.trustedfirmware.org/c/4334
     2. emerge-asurada coreboot chromeos-bootimage
     3. boot asurada

Change-Id: Ieb93073beff7ec95eb5406eecbfba8192f91edce
Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46382
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/mediatek/mt8192/Kconfig b/src/soc/mediatek/mt8192/Kconfig
index 1d1cf7b..18d9d41 100644
--- a/src/soc/mediatek/mt8192/Kconfig
+++ b/src/soc/mediatek/mt8192/Kconfig
@@ -5,6 +5,7 @@
 	select ARCH_VERSTAGE_ARMV8_64
 	select ARCH_ROMSTAGE_ARMV8_64
 	select ARCH_RAMSTAGE_ARMV8_64
+	select ARM64_USE_ARM_TRUSTED_FIRMWARE
 	select HAVE_UART_SPECIAL
 
 if SOC_MEDIATEK_MT8192
diff --git a/src/soc/mediatek/mt8192/Makefile.inc b/src/soc/mediatek/mt8192/Makefile.inc
index b047ce9..fb3b11d 100644
--- a/src/soc/mediatek/mt8192/Makefile.inc
+++ b/src/soc/mediatek/mt8192/Makefile.inc
@@ -36,6 +36,8 @@
 ramstage-y += ../common/uart.c
 ramstage-y += ../common/usb.c usb.c
 
+BL31_MAKEARGS += PLAT=mt8192
+
 CPPFLAGS_common += -Isrc/soc/mediatek/mt8192/include
 CPPFLAGS_common += -Isrc/soc/mediatek/common/include