scsi: smartpqi: unlock on error in pqi_submit_raid_request_synchronous()

We need to drop the "ctrl_info->sync_request_sem" lock before returning.

Fixes: 6c223761

 ("smartpqi: initial commit of Microsemi smartpqi driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>