net/mlx4_core: Add basic support for TCP/IP offloads under tunneling

Add the low-level device commands and definitions used for TCP/IP HW offloads
of tunneled/vxlan traffic which are supported by the ConnectX3-pro NIC.

This is done through the following elements:

 - read tunneling device caps in QUERY_DEV_CAP
 - add helper function to do SET_PORT for tunneling
 - add DMFS VXLAN steering rule definitions
 - add CQE and WQE checksum offload field definitions

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/mlx4/cmd.h b/include/linux/mlx4/cmd.h
index 8df61bc..b0ec0fe 100644
--- a/include/linux/mlx4/cmd.h
+++ b/include/linux/mlx4/cmd.h
@@ -180,6 +180,7 @@
 	MLX4_SET_PORT_GID_TABLE = 0x5,
 	MLX4_SET_PORT_PRIO2TC	= 0x8,
 	MLX4_SET_PORT_SCHEDULER = 0x9,
+	MLX4_SET_PORT_VXLAN	= 0xB
 };
 
 enum {