image: use check-size from new image build code

Use the new image build code and deduplicate the code.

Signed-off-by: Mathias Kresin <dev@kresin.me>

include/image.mk

@@ -422,13 +422,6 @@ define Device/Build/initramfs
 endef
 endif
 
-define Device/Build/check_size
-	@[ $$(($(subst k,* 1024,$(subst m, * 1024k,$(1))))) -ge "$$(stat -c%s $@)" ] || { \
-		echo "WARNING: Image file $@ is too big" >&2; \
-		rm -f $@; \
-	}
-endef
-
 define Device/Build/compile
   $$(_COMPILE_TARGET): $(KDIR)/$(1)
   $(eval $(call Device/Export,$(KDIR)/$(1)))
@@ -450,7 +443,7 @@ define Device/Build/kernel
     $$(KDIR_KERNEL_IMAGE): $(KDIR)/$$(KERNEL_NAME) $(CURDIR)/Makefile $$(KERNEL_DEPENDS)
 	@rm -f $$@
 	$$(call concat_cmd,$$(KERNEL))
-	$$(if $$(KERNEL_SIZE),$$(call Device/Build/check_size,$$(KERNEL_SIZE)))
+	$$(if $$(KERNEL_SIZE),$$(call Build/check-size,$$(KERNEL_SIZE)))
   endif
 endef