[SCSI] mpt3sas: cut and paste bug storing trigger mpi

ioc->diag_trigger_mpi is an SL_WH_MPI_TRIGGERS_T struct.

There is a cut and paste error here and SL_WH_EVENT_TRIGGERS_T is used
instead of SL_WH_MPI_TRIGGERS_T.  Since the SL_WH_EVENT_TRIGGERS_T is
smaller than SL_WH_MPI_TRIGGERS_T, it means we only clear part of the
buffer.

I've changed it to use sizeof(ioc->diag_trigger_mpi) which is a bit
simpler.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: "Sreekanth Reddy" <Sreekanth.reddy@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/mpt3sas/mpt3sas_ctl.c

@@ -3136,7 +3136,7 @@ _ctl_diag_trigger_mpi_store(struct device *cdev,
 	spin_lock_irqsave(&ioc->diag_trigger_lock, flags);
 	sz = min(sizeof(struct SL_WH_MPI_TRIGGERS_T), count);
 	memset(&ioc->diag_trigger_mpi, 0,
-	    sizeof(struct SL_WH_EVENT_TRIGGERS_T));
+	    sizeof(ioc->diag_trigger_mpi));
 	memcpy(&ioc->diag_trigger_mpi, buf, sz);
 	if (ioc->diag_trigger_mpi.ValidEntries > NUM_VALID_ENTRIES)
 		ioc->diag_trigger_mpi.ValidEntries = NUM_VALID_ENTRIES;