firmware-utils: improve tools for Buffalo DHP series

some of Buffalo DHP series use slightly different trx magic, buffalo-enc,
buffalo-tag, and factory image begin with 'bgn'.

this patch adds support for building those images.

Signed-off-by: FUKAUMI Naoki <naobsd@gmail.com>

include/image-commands.mk

@@ -11,6 +11,39 @@ define Build/uImage
 	@mv $@.new $@
 endef
 
+define Build/buffalo-enc
+	$(eval product=$(word 1,$(1)))
+	$(eval version=$(word 2,$(1)))
+	$(eval args=$(wordlist 3,$(words $(1)),$(1)))
+	$(STAGING_DIR_HOST)/bin/buffalo-enc \
+		-p $(product) -v $(version) $(args) \
+		-i $@ -o $@.new
+	mv $@.new $@
+endef
+
+define Build/buffalo-enc-tag
+	$(call Build/buffalo-enc,'' '' -S 152 $(1))
+endef
+
+define Build/buffalo-tag-dhp
+	$(eval product=$(word 1,$(1)))
+	$(eval region=$(word 2,$(1)))
+	$(eval language=$(word 3,$(1)))
+	$(STAGING_DIR_HOST)/bin/buffalo-tag \
+		-d 0x01000000 -w 1 \
+		-a $(BUFFALO_TAG_PLATFORM) \
+		-v $(BUFFALO_TAG_VERSION) -m $(BUFFALO_TAG_MINOR) \
+		-b $(product) -p $(product) \
+		-r $(region) -r $(region) -l $(language) \
+		-I $@ -o $@.new
+	mv $@.new $@
+endef
+
+define Build/buffalo-dhp-image
+	$(STAGING_DIR_HOST)/bin/mkdhpimg $@ $@.new
+	mv $@.new $@
+endef
+
 define Build/netgear-chk
 	$(STAGING_DIR_HOST)/bin/mkchkimg \
 		-o $@.new \