[SCSI] megaraid_sas: Add throttlequeuedepth module parameter

This allows a user to adjust the queue depth of the adapter when throttled due
to I/O timeout.

Signed-off-by: Adam Radford <aradford@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index e8f8926..f65025d 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -747,6 +747,7 @@
 #define	MEGASAS_RESET_NOTICE_INTERVAL		5
 #define MEGASAS_IOCTL_CMD			0
 #define MEGASAS_DEFAULT_CMD_TIMEOUT		90
+#define MEGASAS_THROTTLE_QUEUE_DEPTH		16
 
 /*
  * FW reports the maximum of number of commands that it can accept (maximum
@@ -1364,6 +1365,7 @@
 	unsigned long bar;
 	long reset_flags;
 	struct mutex reset_mutex;
+	int throttlequeuedepth;
 };
 
 enum {