Makefile: Add rockchip image type

Add rockchip image type support. right now the image
type marked with rksd, So create image type variable
with required image type like rksd or rkspi.

Cc: Matwey V. Kornilov <matwey.kornilov@gmail.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/Makefile b/Makefile
index f4de30b..7947f34 100644
--- a/Makefile
+++ b/Makefile
@@ -1378,7 +1378,15 @@
 	$(call if_changed,pad_cat)
 
 ifeq ($(CONFIG_ARCH_ROCKCHIP),y)
-MKIMAGEFLAGS_u-boot-tpl.img = -n $(CONFIG_SYS_SOC) -T rksd
+
+# rockchip image type
+ifeq ($(CONFIG_SPL_SPI_LOAD),y)
+ROCKCHIP_IMG_TYPE := rkspi
+else
+ROCKCHIP_IMG_TYPE := rksd
+endif
+
+MKIMAGEFLAGS_u-boot-tpl.img = -n $(CONFIG_SYS_SOC) -T $(ROCKCHIP_IMG_TYPE)
 tpl/u-boot-tpl.img: tpl/u-boot-tpl.bin FORCE
 	$(call if_changed,mkimage)
 idbloader.img: tpl/u-boot-tpl.img spl/u-boot-spl.bin FORCE