[SCSI] isci: fix missed unlock in apc_agent_timeout()

Needed to jump to scic_lock unlock.

Also spotted by coccicheck.

Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>