Kernel panic may be observed by user, if MR controller is under Chip reset (OCR)
and there are some pending IOs at the time of OCR. This is mainly because of
recursive mutext in OCR and IO completion function call. Generic IO completion (from ISR) needs
sim_lock to be held before it calls completion to CAM (xpt_done), but in case of OCR path mrsas_ocr thread
itself take sim_lock, so this condition is now handled in this patch.

MFC after: 3 days