ramips: consolidate recipes with uimage_padhdr

There are already two very similar recipes using uimage_padhdr
in ramips target, and a third one is about to be added.

Make the recipe more generic, so redefinitions are not necessary
anymore.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Tested-by: Bjørn Mork <bjorn@mork.no> [Zyxel WAP6805]

target/linux/ramips/image/Makefile

@@ -51,11 +51,6 @@ define Build/elx-header
 	rm -rf $(KDIR)/tmp/$(DEVICE_NAME).header
 endef
 
-define Build/fonfxcimage
-	uimage_padhdr -i $@ -o $@.new
-	mv $@.new $@
-endef
-
 define Build/jcg-header
 	$(STAGING_DIR_HOST)/bin/jcgimage -v $(1) \
 		$(if $(JCG_MAXSIZE), -m $$(($(subst k, * 1024,$(JCG_MAXSIZE)))),) \
@@ -151,6 +146,11 @@ define Build/trx
 		-a 4 -f $(IMAGE_ROOTFS)
 endef
 
+define Build/uimage-padhdr
+	uimage_padhdr $(if $(1),-l $(1)) -i $@ -o $@.new
+	mv $@.new $@
+endef
+
 define Build/umedia-header
 	fix-u-media-header -T 0x46 -B $(1) -i $@ -o $@.new && mv $@.new $@
 endef

target/linux/ramips/image/mt7620.mk

@@ -400,8 +400,8 @@ define Device/fon_fon2601
   DEVICE_VENDOR := Fon
   DEVICE_MODEL := FON2601
   DEVICE_PACKAGES := kmod-mt76x2 kmod-usb2 kmod-usb-ohci
-  KERNEL_INITRAMFS := $$(KERNEL) | fonfxcimage
-  IMAGE/sysupgrade.bin := append-kernel | append-rootfs | fonfxcimage | \
+  KERNEL_INITRAMFS := $$(KERNEL) | uimage-padhdr
+  IMAGE/sysupgrade.bin := append-kernel | append-rootfs | uimage-padhdr | \
 	pad-rootfs | append-metadata | check-size
 endef
 TARGET_DEVICES += fon_fon2601

target/linux/ramips/image/mt7621.mk

@@ -81,11 +81,6 @@ define Build/iodata-mstc-header
 	)
 endef
 
-define Build/mitrastarimage
-	uimage_padhdr -l 160 -i $@ -o $@.new
-	mv $@.new $@
-endef
-
 define Build/ubnt-erx-factory-image
 	if [ -e $(KDIR)/tmp/$(KERNEL_INITRAMFS_IMAGE) -a "$$(stat -c%s $@)" -lt "$(KERNEL_SIZE)" ]; then \
 		echo '21001:7' > $(1).compat; \
@@ -1146,7 +1141,7 @@ define Device/zyxel_wap6805
   DEVICE_VENDOR := ZyXEL
   DEVICE_MODEL := WAP6805
   DEVICE_PACKAGES := kmod-mt7603 wpad-basic kmod-mt7621-qtn-rgmii
-  KERNEL := $(KERNEL_DTB) | uImage lzma | mitrastarimage
+  KERNEL := $(KERNEL_DTB) | uImage lzma | uimage-padhdr 160
   IMAGE/sysupgrade.bin := sysupgrade-tar | append-metadata
 endef
 TARGET_DEVICES += zyxel_wap6805