scsi: mpt3sas: clean up a couple sizeof() uses

There is a copy and paste bug here.  It uses EVENT_TRIGGERS size instead of
SCSI_TRIGGERS size but fortunately both size are 84 bytes so it doesn't
affect runtime.

These days the preferred style is to just say sizeof(object) instead of
sizeof(type) so I have updated the function to the latest style as well.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>