hpsa: do not ack controller events on controllers that do not support it

Acking controller events on controllers that do not support
it can cause such controllers to lock up.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NJoe Handzik <joseph.t.handzik@hp.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

drivers/scsi/hpsa.c

@@ -6674,6 +6674,9 @@ static void hpsa_ack_ctlr_events(struct ctlr_info *h)
 	int i;
 	char *event_type;
 
+	if (!(h->fw_support & MISC_FW_EVENT_NOTIFY))
+		return;
+
 	/* Ask the controller to clear the events we're handling. */
 	if ((h->transMethod & (CFGTBL_Trans_io_accel1
 			| CFGTBL_Trans_io_accel2)) &&