[SCSI] qla2xxx: Correct out of bounds read of ISP2200 mailbox registers.

ISP2200 adapters only have 24 mailbox registers so read only that many.

Reported-by: Olatunji Ruwase <oor@cs.cmu.edu>
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 5fd89d7..7e617a6 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -2054,7 +2054,7 @@
 		ha->nvram_data_off = ~0;
 		ha->isp_ops = &qla2100_isp_ops;
 	} else if (IS_QLA2200(ha)) {
-		ha->mbx_count = MAILBOX_REGISTER_COUNT;
+		ha->mbx_count = MAILBOX_REGISTER_COUNT_2200;
 		req_length = REQUEST_ENTRY_CNT_2200;
 		rsp_length = RESPONSE_ENTRY_CNT_2100;
 		ha->max_loop_id = SNS_LAST_LOOP_ID_2100;