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: NJagan Teki <jagan@amarulasolutions.com>
Reviewed-by: NKever Yang <kever.yang@rock-chips.com>

Makefile

@@ -1378,7 +1378,15 @@ u-boot-with-spl.bin: $(SPL_IMAGE) $(SPL_PAYLOAD) FORCE
 	$(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