build: move Build/edimax-header to image-commands.mk

To use from the following devices in ath79 target, move edimax-header to
image-commands.mk.

- ELECOM WRC-300GHBK2-I
- ELECOM WRC-1750GHBK2-I/C

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

include/image-commands.mk

@@ -218,6 +218,11 @@ define Build/copy-file
 	cat "$(1)" > "$@"
 endef
 
+define Build/edimax-header
+	$(STAGING_DIR_HOST)/bin/mkedimaximg -i $@ -o $@.new $(1)
+	@mv $@.new $@
+endef
+
 define Build/elecom-product-header
 	$(eval product=$(word 1,$(1)))
 	$(eval fw=$(if $(word 2,$(1)),$(word 2,$(1)),$@))

target/linux/ramips/image/Makefile

@@ -28,11 +28,6 @@ LOADER_FLASH_START := $(ldrflashstart-y)
 
 KERNEL_DTB = kernel-bin | append-dtb | lzma
 
-define Build/edimax-header
-	$(STAGING_DIR_HOST)/bin/mkedimaximg -i $@ -o $@.new $(1)
-	@mv $@.new $@
-endef
-
 define Build/jcg-header
 	$(STAGING_DIR_HOST)/bin/jcgimage -v $(1) \
 		$(if $(JCG_MAXSIZE), -m $$(($(subst k, * 1024,$(JCG_MAXSIZE)))),) \