imx: mkimage: avoid stop CI when required files not exists

Introduce a new script to check whether file exists and
use that check in Makefile to avoid break CI system.

The script return 1 when the required files not exists, return 0
when files exists. The script will ignore check to u-boot-dtb.bin,
because if there is something wrong to generate u-boot-dtb.bin,
there must be some code error.

Signed-off-by: Peng Fan <peng.fan@nxp.com>

arch/arm/mach-imx/Makefile

@@ -86,9 +86,13 @@ IMX_CONFIG = $(CONFIG_IMX_CONFIG:"%"=%)
 	$(Q)mkdir -p $(dir $@)
 	$(call if_changed_dep,cpp_cfg)
 
-IMAGE_TYPE = imximage
 ifeq ($(CONFIG_ARCH_IMX8), y)
-IMAGE_TYPE = imx8image
+CNTR_DEPFILES := $(srctree)/tools/imx_cntr_image.sh
+IMAGE_TYPE := imx8image
+DEPFILE_EXISTS := $(shell if [ -f u-boot-dtb.cfgout ]; then $(CNTR_DEPFILES) u-boot-dtb.cfgout; echo $$?; fi)
+else
+IMAGE_TYPE := imximage
+DEPFILE_EXISTS := 0
 endif
 
 MKIMAGEFLAGS_u-boot.imx = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) \
@@ -104,8 +108,10 @@ MKIMAGEFLAGS_u-boot-dtb.imx = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) \
 u-boot-dtb.imx: MKIMAGEOUTPUT = u-boot-dtb.imx.log
 
 u-boot-dtb.imx: u-boot-dtb.bin u-boot-dtb.cfgout $(PLUGIN).bin FORCE
+ifeq ($(DEPFILE_EXISTS),0)
 	$(call if_changed,mkimage)
 endif
+endif
 
 MKIMAGEFLAGS_SPL = -n $(filter-out $(PLUGIN).bin $< $(PHONY),$^) \
 		   -T $(IMAGE_TYPE) -e $(CONFIG_SPL_TEXT_BASE)