jbd2: Convert journal commit to bh_submit()

jbd2: Convert journal commit to bh_submit()

Avoid an extra indirect function call by using bh_submit()
instead of submit_bh() in journal_submit_commit_record()
and jbd2_journal_commit_transaction().  These both use
journal_end_buffer_io_sync(), so it's more straightforward to do them
both at once.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-17-willy@infradead.org
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>