atomisp: don't leave mutex locked

atomisp: don't leave mutex locked

BZ: 23514

In case of timeout the lock left untouched.

This patch fixes following bug.

[   73.121283] BUG: workqueue leaked lock or atomic: kworker/u:0/0x00000000/5
[   73.121311]     last function: atomisp_work+0x0/0x6ef [atomisp]
[   73.121466] 1 lock held by kworker/u:0/5:
[   73.121486]  #0:  (&isp->isp_lock){+.+.+.}, at: [<f978e8e5>] atomisp_work+0x369/0x6ef [atomisp]
[   73.121664] Pid: 5, comm: kworker/u:0 Tainted: G        W   3.0.13-mid4-02284-g2796f20-dirty #149
[   73.121690] Call Trace:
[   73.121735]  [<c1034497>] ? console_unlock+0x178/0x18a
[   73.121844]  [<c1048240>] process_one_work+0x2b0/0x32c
[   73.121984]  [<f978e57c>] ? atomisp_buffer_dequeue+0x9b/0x9b [atomisp]
[   73.122588]  [<c1048ffb>] worker_thread+0xbb/0x136
[   73.122632]  [<c1048f40>] ? manage_workers.isra.24+0x150/0x150
[   73.122672]  [<c104bf09>] kthread+0x73/0x78
[   73.122718]  [<c104be96>] ? __init_kthread_worker+0x47/0x47
[   73.122763]  [<c14df342>] kernel_thread_helper+0x6/0x10

Change-Id: I2059b6db63bfa0d9ae4baed0353a0304907dd33f
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@intel.com>
Reviewed-on: http://android.intel.com:8080/34937
Reviewed-by: Cohen, David A <david.a.cohen@intel.com>
Reviewed-by: Shevchenko, Andriy <andriy.shevchenko@intel.com>
Reviewed-by: Toivonen, Tuukka <tuukka.toivonen@intel.com>
Reviewed-by: Koskinen, Ilkka <ilkka.koskinen@intel.com>
Reviewed-by: Wang, Wen W <wen.w.wang@intel.com>
Reviewed-by: Tuominen, TeemuX <teemux.tuominen@intel.com>
Tested-by: Koski, Anttu <anttu.koski@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>