rockchip: Add proper dependency tracking to M0 Makefile

This patch adds dependency rule generation and inclusion to the M0
Makefile, so that M0 objects will get correctly remade with an
incremental build if a header file they included changed.

Change-Id: I2067bd9fd4d9dad3e77a09cbf09c7b4db3c1eda5
Signed-off-by: Julius Werner <jwerner@chromium.org>

plat/rockchip/rk3399/drivers/m0/Makefile

@@ -91,10 +91,11 @@ BIN 			:= $(BUILD)/$(PLAT_M0).bin
 # Function definition related compilation
 define MAKE_C
 $(eval OBJ := $(1)/$(patsubst %.c,%.o,$(notdir $(2))))
+-include $(patsubst %.o,%.d,$(OBJ))
 
 $(OBJ) : $(2)
 	@echo "  CC      $$<"
-	$$(Q)$$(CC) $$(CFLAGS) $$(INCLUDES) -c $$< -o $$@
+	$$(Q)$$(CC) $$(CFLAGS) $$(INCLUDES) -MMD -MT $$@ -c $$< -o $$@
 endef
 
 define MAKE_S