[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_def.h b/drivers/scsi/qla2xxx/qla_def.h
index a6a4eeb..af1003f 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -44,6 +44,7 @@
  * ISP2100 HBAs.
  */
 #define MAILBOX_REGISTER_COUNT_2100	8
+#define MAILBOX_REGISTER_COUNT_2200	24
 #define MAILBOX_REGISTER_COUNT		32
 
 #define QLA2200A_RISC_ROM_VER	4