scsi: mpt3sas: Increase event log buffer to support 24 port HBA's.

For 24 port HBA's events generated by IOC are more in certain cases and
the current circular buffer may be overwritten.Hence increased the event
log buffer to accommodate more events.

Signed-off-by: Chaitra P B <chaitra.basappa@broadcom.com>
Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>