net/mlx4: mlx4_config_dev_retrieval() - Initialize struct config_dev before using

Add Initialization to struct config_dev before filling and using it.
Fix to warning:

warning: config_dev.rx_checksum_val may be used uninitialized in this function
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -2169,7 +2169,7 @@ static const u8 config_dev_csum_flags[] = {
 int mlx4_config_dev_retrieval(struct mlx4_dev *dev,
 			      struct mlx4_config_dev_params *params)
 {
-	struct mlx4_config_dev config_dev;
+	struct mlx4_config_dev config_dev = {0};
 	int err;
 	u8 csum_mask;