feat(plat/mediatek/mt8195): add vcore-dvfs support

Add DVFSRC init flow.

Change-Id: Ic5fc78c91359abc12c0f54b01860a7cbe41f3358
diff --git a/plat/mediatek/mt8195/drivers/spm/build.mk b/plat/mediatek/mt8195/drivers/spm/build.mk
index d1ee092..28b2d07 100644
--- a/plat/mediatek/mt8195/drivers/spm/build.mk
+++ b/plat/mediatek/mt8195/drivers/spm/build.mk
@@ -30,7 +30,8 @@
 	${CUR_SPM_FOLDER}/constraints/mt_spm_rc_syspll.c	\
 	${CUR_SPM_FOLDER}/mt_spm_cond.c				\
 	${CUR_SPM_FOLDER}/mt_spm_suspend.c			\
-	${CUR_SPM_FOLDER}/mt_spm_idle.c
+	${CUR_SPM_FOLDER}/mt_spm_idle.c				\
+	${CUR_SPM_FOLDER}/mt_spm_vcorefs.c
 
 ifeq (${MT_SPM_FEATURE_SUPPORT}, no)
 PLAT_SPM_DEBUG_CFLAGS += -DATF_PLAT_SPM_UNSUPPORT