net/mlx4_en: set correct MTU in SRIOV

When setting MTU in SRIOV mode add ETH, VLAN and FCS header length
to the maximum MTU obtained from QUERY_DEV_CAP.
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/port.c

@@ -32,6 +32,7 @@
 
 #include <linux/errno.h>
 #include <linux/if_ether.h>
+#include <linux/if_vlan.h>
 #include <linux/export.h>
 
 #include <linux/mlx4/cmd.h>
@@ -517,7 +518,8 @@ static int mlx4_common_set_port(struct mlx4_dev *dev, int slave, u32 in_mod,
 			/* Mtu is configured as the max MTU among all the
 			 * the functions on the port. */
 			mtu = be16_to_cpu(gen_context->mtu);
-			mtu = min_t(int, mtu, dev->caps.eth_mtu_cap[port]);
+			mtu = min_t(int, mtu, dev->caps.eth_mtu_cap[port] +
+				    ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
 			prev_mtu = slave_st->mtu[port];
 			slave_st->mtu[port] = mtu;
 			if (mtu > master->max_mtu[port])