scsi: mpi3mr: Add support for PEL commands

scsi: mpi3mr: Add support for PEL commands

Implement driver support for management applications to enable persistent
event log (PEL) notifications. Upon receipt of events, the driver will
increment a sysfs variable named event_counter. The management application
will poll for event_counter value changes and signal the application about
events.

Link: https://lore.kernel.org/r/20220429211641.642010-6-sumit.saxena@broadcom.com
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>