If we return 1 here, then the caller treats it as an error and returns
-EINVAL.  It causes a static checker warning to treat positive returns
as an error.

Fixes: 1aba86d6 ('Btrfs: fix easily get into ENOSPC in mixed case')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>