btrfs: do not clean up repair bio if submit fails

btrfs: do not clean up repair bio if submit fails

The submit helper will always run bio_endio() on the bio if it fails to
submit, so cleaning up the bio just leads to a variety of UAF and NULL
pointer deref bugs because we race with the endio function that is
cleaning up the bio.  Instead just return STS_OK as the repair function
has to continue to process the rest of the pages, and the endio for the
repair bio will do the appropriate cleanup for the page that it was
given.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>