net/mlx5: sparse: warning: Using plain integer as NULL pointer

Return NULL instead of 0.
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Moshe Shemesh <moshe@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/lib/dm.c

@@ -21,7 +21,7 @@ struct mlx5_dm *mlx5_dm_create(struct mlx5_core_dev *dev)
 	struct mlx5_dm *dm;
 
 	if (!(MLX5_CAP_GEN_64(dev, general_obj_types) & MLX5_GENERAL_OBJ_TYPES_CAP_SW_ICM))
-		return 0;
+		return NULL;
 
 	dm = kzalloc(sizeof(*dm), GFP_KERNEL);
 	if (!dm)