jfs: fix log->bdev_handle null ptr deref in lbmStartIO

[ Upstream commit 6306ff39

 ]

When sbi->flag is JFS_NOINTEGRITY in lmLogOpen(), log->bdev_handle can't
be inited, so it value will be NULL.
Therefore, add the "log ->no_integrity=1" judgment in lbmStartIO() to avoid such
problems.

Reported-and-tested-by:  <syzbot+23bc20037854bb335d59@syzkaller.appspotmail.com>
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Link: https://lore.kernel.org/r/20231009094557.1398920-1-lizhi.xu@windriver.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>