build: move xor-image into image-commands

I moved xor-image into image-commands.mk to use it in ath79 target.

It required for NEC WG800HP.

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

include/image-commands.mk

@@ -242,6 +242,11 @@ define Build/pad-offset
 	mv $@.new $@
 endef
 
+define Build/xor-image
+	$(STAGING_DIR_HOST)/bin/xorimage -i $@ -o $@.xor $(1)
+	mv $@.xor $@
+endef
+
 define Build/check-size
 	@[ $$(($(subst k,* 1024,$(subst m, * 1024k,$(1))))) -ge "$$(stat -c%s $@)" ] || { \
 		echo "WARNING: Image file $@ is too big" >&2; \

target/linux/brcm63xx/image/Makefile

@@ -132,11 +132,6 @@ define Build/spw303v-bin
 	mv $@.spw303v $@
 endef
 
-define Build/xor-image
-	$(STAGING_DIR_HOST)/bin/xorimage -i $@ -o $@.xor
-	mv $@.xor $@
-endef
-
 define Build/zyxel-bin
 	$(STAGING_DIR_HOST)/bin/zyxbcm -i $@ -o $@.zyxel
 	mv $@.zyxel $@