feat(mt8186): add DFD control in SiP service

DFD (Design for Debug) is a debugging tool, which scans flip-flops and
dumps to internal RAM on the WDT reset. After system reboots, those
values could be showed for debugging.

BUG=b:222217317
TEST=build pass

Change-Id: I659ea1e0789cf135a71a13b752edaa35123e0941
diff --git a/plat/mediatek/mt8186/platform.mk b/plat/mediatek/mt8186/platform.mk
index 6108a05..b6d9ca8 100644
--- a/plat/mediatek/mt8186/platform.mk
+++ b/plat/mediatek/mt8186/platform.mk
@@ -15,6 +15,7 @@
 		 -I${MTK_PLAT}/common/lpm/                        \
                  -I${MTK_PLAT_SOC}/drivers/spm/                   \
                  -I${MTK_PLAT_SOC}/drivers/dcm/                   \
+                 -I${MTK_PLAT_SOC}/drivers/dfd/                    \
                  -I${MTK_PLAT_SOC}/drivers/emi_mpu/               \
                  -I${MTK_PLAT_SOC}/drivers/gpio/               \
                  -I${MTK_PLAT_SOC}/drivers/mcdi/                  \
@@ -58,6 +59,7 @@
                 ${MTK_PLAT_SOC}/bl31_plat_setup.c                     \
                 ${MTK_PLAT_SOC}/drivers/dcm/mtk_dcm.c                 \
                 ${MTK_PLAT_SOC}/drivers/dcm/mtk_dcm_utils.c           \
+                ${MTK_PLAT_SOC}/drivers/dfd/plat_dfd.c                \
                 ${MTK_PLAT_SOC}/drivers/emi_mpu/emi_mpu.c             \
                 ${MTK_PLAT_SOC}/drivers/gpio/mtgpio.c                 \
                 ${MTK_PLAT_SOC}/drivers/mcdi/mt_cpu_pm.c              \