build: allow passing parameters to padjffs2 via the pad-rootfs command

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44015 3c298f89-4303-0410-b956-a3cf2f4a3e73

include/image.mk

@@ -304,7 +304,7 @@ define Build/append-rootfs
 endef
 
 define Build/pad-rootfs
-	$(call prepare_generic_squashfs,$@)
+	$(call prepare_generic_squashfs,$@ $(1))
 endef
 
 define Build/pad-offset