mediatek: mt8192: Add SPM suspend driver

Supports dram/mainpll/26m off when system suspend

Change-Id: Id13a06d4132f00fb60066de75920ecac18306e32
diff --git a/plat/mediatek/mt8192/platform.mk b/plat/mediatek/mt8192/platform.mk
index e4994e6..0b35d06 100644
--- a/plat/mediatek/mt8192/platform.mk
+++ b/plat/mediatek/mt8192/platform.mk
@@ -69,6 +69,9 @@
                    ${MTK_PLAT_SOC}/drivers/spmc/mtspmc.c                 \
                    ${MTK_PLAT_SOC}/drivers/timer/mt_timer.c
 
+# Build SPM drivers
+include ${MTK_PLAT_SOC}/drivers/spm/build.mk
+
 # Configs for A76 and A55
 HW_ASSISTED_COHERENCY := 1
 USE_COHERENT_MEM := 0