base-files: fwtool: Fix wrong checksum on combined-image with metadata

If I create following image:

define Device/engenius-m36
  IMAGE/sysupgrade.bin := combined-image | append-metadata
endef

Sysupgrade then errors out:

  Invalid image. Contents do not match checksum (image:cd285595eaf297370404ae0e2815ec1a calculated:2cf9a2286fb6b01af3ea189128017d44)
  Image check 'platform_check_image' failed.

By removing the metadata from the image I get combined-image checksum
working again and sysupgrade works.

Signed-off-by: Petr Štetiar <ynezz@true.cz>

package/base-files/files/lib/upgrade/fwtool.sh

@@ -28,7 +28,7 @@ fwtool_check_image() {
 
 	. /usr/share/libubox/jshn.sh
 
-	if ! fwtool -q -i /tmp/sysupgrade.meta "$1"; then
+	if ! fwtool -q -t -i /tmp/sysupgrade.meta "$1"; then
 		echo "Image metadata not found"
 		[ "$REQUIRE_IMAGE_METADATA" = 1 -a "$FORCE" != 1 ] && {
 			echo "Use sysupgrade -F to override this check when downgrading or flashing to vendor firmware"