[SCSI] mpt2sas: Change in MPI2_RAID_ACTION_SYSTEM_SHUTDOWN_INITIATED notification methodology

The intent of this patch is to perform a graceful shutdown of target drives even if
volume doesn't exits. Changes done in this patch

1. Removed the check for the presence of volumes before sending down
   MPI2_RAID_ACTION_SYSTEM_SHUTDOWN_INITIATED. Therefore, this RAID action
   would be sent if the card is IR Firmware.

2. The MPI2_RAID_ACTION_SYSTEM_SHUTDOWN_INITIATED is sent even when the
   system undergoes suspend (in addition to remove/shutdown which was already
   present)

Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>