brcm63xx: move gzip build command to include/image.mk

Allow other targets to make use of it.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>

SVN-Revision: 46601

include/image.mk

@@ -323,6 +323,11 @@ define Build/lzma
 	@mv $@.new $@
 endef
 
+define Build/gzip
+	gzip -9n -c $@ $(1) > $@.new
+	@mv $@.new $@
+endef
+
 define Build/kernel-bin
 	rm -f $@
 	cp $^ $@

target/linux/brcm63xx/image/Makefile

@@ -38,11 +38,6 @@ define Build/append-dtb
 	cat $@.dtb >> $@
 endef
 
-define Build/gzip
-	gzip -9 -c $@ > $@.gz
-	mv $@.gz $@
-endef
-
 define Build/hcs-initramfs
 	$(STAGING_DIR_HOST)/bin/hcsmakeimage --magic_bytes=$(HCS_MAGIC_BYTES) \
 		--rev_maj=$(HCS_REV_MAJ) --rev_min=$(HCS_REV_MIN) --input_file=$@ \