[SCSI] qla2xxx: Don't depend on mailbox return values while enabling FCE tracing.

Recent firmwares no longer return the 'number of buffers' in
mailbox6.  The original code may result in a potential panic
during a FW-dump process due to the driver misinterpreting the
size of the allocated buffer.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/qla2xxx/qla_mbx.c b/drivers/scsi/qla2xxx/qla_mbx.c
index 3800876..bf3a6f0 100644
--- a/drivers/scsi/qla2xxx/qla_mbx.c
+++ b/drivers/scsi/qla2xxx/qla_mbx.c
@@ -2508,7 +2508,7 @@
 		if (mb)
 			memcpy(mb, mcp->mb, 8 * sizeof(*mb));
 		if (dwords)
-			*dwords = mcp->mb[6];
+			*dwords = buffers;
 	}
 
 	return rval;