arm: imx: include imx8image support

When building i.MX8/8X board, use imx8image type.

`-e $(CONFIG_SYS_TEXT_BASE)` is not needed, but
no harm to keep it for i.MX8/8X

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index d6dcbe0..2d79c71 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -86,24 +86,29 @@
 	$(Q)mkdir -p $(dir $@)
 	$(call if_changed_dep,cpp_cfg)
 
-MKIMAGEFLAGS_u-boot.imx = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) -T imximage \
-	-e $(CONFIG_SYS_TEXT_BASE)
+IMAGE_TYPE = imximage
+ifeq ($(CONFIG_ARCH_IMX8), y)
+IMAGE_TYPE = imx8image
+endif
+
+MKIMAGEFLAGS_u-boot.imx = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) \
+	-T $(IMAGE_TYPE) -e $(CONFIG_SYS_TEXT_BASE)
 u-boot.imx: MKIMAGEOUTPUT = u-boot.imx.log
 
 u-boot.imx: u-boot.bin u-boot.cfgout $(PLUGIN).bin FORCE
 	$(call if_changed,mkimage)
 
 ifeq ($(CONFIG_OF_SEPARATE),y)
-MKIMAGEFLAGS_u-boot-dtb.imx = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) -T imximage \
-	-e $(CONFIG_SYS_TEXT_BASE)
+MKIMAGEFLAGS_u-boot-dtb.imx = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) \
+	-T $(IMAGE_TYPE) -e $(CONFIG_SYS_TEXT_BASE)
 u-boot-dtb.imx: MKIMAGEOUTPUT = u-boot-dtb.imx.log
 
 u-boot-dtb.imx: u-boot-dtb.bin u-boot-dtb.cfgout $(PLUGIN).bin FORCE
 	$(call if_changed,mkimage)
 endif
 
-MKIMAGEFLAGS_SPL = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) -T imximage \
-	-e $(CONFIG_SPL_TEXT_BASE)
+MKIMAGEFLAGS_SPL = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) \
+		   -T $(IMAGE_TYPE) -e $(CONFIG_SPL_TEXT_BASE)
 SPL: MKIMAGEOUTPUT = SPL.log
 
 SPL: spl/u-boot-spl.bin spl/u-boot-spl.cfgout $(PLUGIN).bin FORCE