net/mlx4_en: adding loopback support

Device must be in promiscuous mode or DMAC must be same as the host MAC, or
else packet will be dropped by the HW rx filtering.

Signed-off-by: Amir Vadai <amirv@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/mlx4/qp.h b/include/linux/mlx4/qp.h
index 6562ff6..bee8fa2 100644
--- a/include/linux/mlx4/qp.h
+++ b/include/linux/mlx4/qp.h
@@ -210,6 +210,7 @@
 	 * [4]   IP checksum
 	 * [3:2] C (generate completion queue entry)
 	 * [1]   SE (solicited event)
+	 * [0]   FL (force loopback)
 	 */
 	__be32			srcrb_flags;
 	/*