fs/ufs: revert "ufs: fix deadlocks introduced by sb mutex merge"

This reverts commit 9ef7db7f ("ufs: fix deadlocks introduced by sb
mutex merge") That patch tried to solve commit 0244756e ("ufs: sb
mutex merge + mutex_destroy") which is itself partially reverted due to
multiple deadlocks.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Suggested-by: Jan Kara <jack@suse.cz>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Roger Pau Monne <roger.pau@citrix.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>