net/mlx4_en: mlx4_en_verify_params() can be static

Fix static error introduced by commit:
b97b33a3 [645/653] net/mlx4_en: Verify
mlx4_en module parameters

sparse warnings:
drivers/net/ethernet/mellanox/mlx4/en_main.c:335:6: sparse: symbol
'mlx4_en_verify_params' was not declared. Should it be static?

CC: netdev@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -332,7 +332,7 @@ static struct mlx4_interface mlx4_en_interface = {
 	.protocol	= MLX4_PROT_ETH,
 };
 
-void mlx4_en_verify_params(void)
+static void mlx4_en_verify_params(void)
 {
 	if (pfctx > MAX_PFC_TX) {
 		pr_warn("mlx4_en: WARNING: illegal module parameter pfctx 0x%x - should be in range 0-0x%x, will be changed to default (0)\n",