net/mlx5e: Don't access directly DMA device pointer

Use specialized helper to fetch DMA device pointer.
Reviewed-by: NSaeed Mahameed <saeedm@nvidia.com>
Signed-off-by: NLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: NSaeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c

@@ -186,7 +186,7 @@ static int mlx5e_macsec_aso_reg_mr(struct mlx5_core_dev *mdev, struct mlx5e_macs
 		return err;
 	}
 
-	dma_device = &mdev->pdev->dev;
+	dma_device = mlx5_core_dma_dev(mdev);
 	dma_addr = dma_map_single(dma_device, umr->ctx, sizeof(umr->ctx), DMA_BIDIRECTIONAL);
 	err = dma_mapping_error(dma_device, dma_addr);
 	if (err) {