Add mtk-mkimage as build dependency for creating bootloader image.

Change-Id: I5600558fa32ae6add71f28993f1c7d1b46c724bb
diff --git a/packages.mk b/packages.mk
index 8d642fd..9eb3c9c 100644
--- a/packages.mk
+++ b/packages.mk
@@ -14,7 +14,7 @@
 
 $(eval $(call make-pbuilder-bsp-package-target,u-boot-mkimage,bootloader/mtk-tools/u-boot-mkimage))
 $(eval $(call make-pbuilder-bsp-package-target,linux-mtk,linux,u-boot-mkimage boot-keys))
-$(eval $(call make-pbuilder-bsp-package-target,lk-bootloader,bootloader))
+$(eval $(call make-pbuilder-bsp-package-target,lk-bootloader,bootloader, u-boot-mkimage))
 $(eval $(call make-pbuilder-bsp-package-target,trustzone,trustzone,boot-keys))
 $(eval $(call make-pbuilder-bsp-package-target,boot-keys,bootloader/mtk-tools/keys,u-boot-mkimage))
 $(eval $(call make-pbuilder-bsp-package-target,excelsior-wlan,packages/excelsior-wlan))