brcm2708: use BuildDTB in image/Makefile

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@46639 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/brcm2708/image/Makefile

@@ -23,7 +23,7 @@ endif
 
 ### Image scripts ###
 define Build/build-dtb
-	$(LINUX_DIR)/scripts/dtc/dtc -O dtb -o $@.dtb $(DTS_DIR)/$(DEVICE_DTS).dts
+	$(call Image/BuildDTB,$(DTS_DIR)/$(DEVICE_DTS).dts,$@.dtb)
 endef
 
 define Build/gen-cfg