net/mlx5e: Implement DCBNL IEEE max rate

Add support for DCBNL IEEE get/set max rate.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/mlx5/device.h

@@ -350,6 +350,12 @@ enum {
 	MLX5_SET_PORT_PKEY_TABLE	= 20,
 };
 
+enum {
+	MLX5_BW_NO_LIMIT   = 0,
+	MLX5_100_MBPS_UNIT = 3,
+	MLX5_GBPS_UNIT	   = 4,
+};
+
 enum {
 	MLX5_MAX_PAGE_SHIFT		= 31
 };