jbd2: remove unused return info from jbd2_journal_write_metadata_buffer

The done_copy_out info from jbd2_journal_write_metadata_buffer is not
used. Simply remove it.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20240514112438.1269037-3-shikemeng@huaweicloud.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>