[SCSI] mvsas: expander write performance enhancement

with 1 expander, connect 8 HDD, the write performance will be
improved by 80%.

Signed-off-by: Xiangliang Yu <yuxiangl@marvell.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/mvsas/mv_defs.h b/drivers/scsi/mvsas/mv_defs.h
index dec7cad..8e21482 100644
--- a/drivers/scsi/mvsas/mv_defs.h
+++ b/drivers/scsi/mvsas/mv_defs.h
@@ -387,6 +387,7 @@
 	CMD_SL_MODE0		= 0x1BC, /* SL Mode 0 */
 	CMD_SL_MODE1		= 0x1C0, /* SL Mode 1 */
 	CMD_PND_FIFO_CTL1	= 0x1C4, /* Pending FIFO Control 1 */
+	CMD_PORT_LAYER_TIMER1	= 0x1E0, /* Port Layer Timer 1 */
 };
 
 enum mvs_info_flags {