selftests: ublk: add missing gitignore for metadata_size binary

A new utility metadata_size was added in
commit 261b67f ("selftests: ublk: add utility to get block device metadata size")
but it was not added to .gitignore. Fix that by adding it there.

While at it sort all entries alphabetically and add a SPDX license header.

Reviewed-by: Caleb Sander Mateos <[email protected]>
Fixes: 261b67f ("selftests: ublk: add utility to get block device metadata size")
Signed-off-by: Alexander Atanasov <[email protected]>
Reviewed-by: Ming Lei <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: zazolabs

tools/testing/selftests/ublk/.gitignore

@@ -1,3 +1,5 @@
-kublk
-/tools
+# SPDX-License-Identifier: GPL-2.0
 *-verify.state
+/tools
+kublk
+metadata_size