scsi: mpi3mr: Support Prepare for Reset event

The IOC sends a Prepare for Reset Event to the host to prepare for a Soft
Reset. This event data has two reason codes:

 1. Start - The host is expected to gracefully quiesce all I/O within
    approximately 1 second.

 2. Abort - The IOC is requesting to abort a previous Prepare for Reset
    Event request. Normal I/O may be resumed.

Link: https://lore.kernel.org/r/20211220141159.16117-20-sreekanth.reddy@broadcom.com
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>