mlx4_en: Fix QP number calculation according to module param

Number of bits taken from mac table index in QP
calculation should be based on log_num_mac parameter.
Signed-off-by: Alexander Guller <alexg@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -128,7 +128,7 @@ int mlx4_SET_PORT_qpn_calc(struct mlx4_dev *dev, u8 port, u32 base_qpn,
 	memset(context, 0, sizeof *context);
 
 	context->base_qpn = cpu_to_be32(base_qpn);
-	context->n_mac = 0x2;
+	context->n_mac = dev->caps.log_num_macs;
 	context->promisc = cpu_to_be32(promisc << SET_PORT_PROMISC_SHIFT |
 				       base_qpn);
 	context->mcast = cpu_to_be32(m_promisc << SET_PORT_MC_PROMISC_SHIFT |