x86: use qemu-image command from image-commands.mk

The `qemu-image` command converts images to the specified type and
reduces redundant code.

Adaption from Alexander Couzens <lynxis@fe80.eu> work[0].

[0]: https://git.openwrt.org/?p=openwrt/staging/lynxis.git;a=blob;f=target/linux/x86/image/Makefile;h=83b8140b7aefbe708fd09c9c61827e7e39bda8b4;hb=416cccf398e9589e3de386e05b61b1c46cace20d#l51

Signed-off-by: Paul Spooren <mail@aparcar.org>

include/image-commands.mk

@@ -414,3 +414,10 @@ define Build/kernel2minor
 	kernel2minor -k $@ -r $@.new $(1)
 	mv $@.new $@
 endef
+
+# Convert a raw image into a $1 type image.
+# E.g. | qemu-image vdi
+define Build/qemu-image
+	qemu-img convert -f raw -O $1 $@ $@.new
+	@mv $@.new $@
+endef

target/linux/x86/image/Makefile

@@ -92,23 +92,13 @@ define Build/iso
 		-o $@ $@.boot $(TARGET_DIR)
 endef
 
-define Build/vdi
-	qemu-img convert -f raw -O vdi $@ $@.new
-	@mv $@.new $@
-endef
-
-define Build/vmdk
-	qemu-img convert -f raw -O vmdk $@ $@.new
-	@mv $@.new $@
-endef
-
 DEVICE_VARS += GRUB2_VARIANT
 define Device/Default
   ARTIFACT/image.iso := grub-config iso | iso
   IMAGES := combined.img.gz
   IMAGE/combined.img.gz := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | gzip
-  IMAGE/combined.vdi := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | vdi
-  IMAGE/combined.vmdk := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | vmdk
+  IMAGE/combined.vdi := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | qemu-image vdi
+  IMAGE/combined.vmdk := append-rootfs | pad-extra 128k | grub-config pc | combined | grub-install | qemu-image vmdk
   KERNEL := kernel-bin
   KERNEL_INSTALL := 1
   KERNEL_NAME := bzImage