net/mlx5: Fix access to sf_dev_table on allocation failure

Even when SF devices are supported, the SF device table allocation
can still fail.
In such case mlx5_sf_dev_supported still reports true, but SF device
table is invalid. This can result in NULL table access.

Hence, fix it by adding NULL table check.

Fixes: 1958fc2f ("net/mlx5: SF, Add auxiliary device driver")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/sf/dev/dev.c

@@ -30,10 +30,7 @@ bool mlx5_sf_dev_allocated(const struct mlx5_core_dev *dev)
 {
 	struct mlx5_sf_dev_table *table = dev->priv.sf_dev_table;
 
-	if (!mlx5_sf_dev_supported(dev))
-		return false;
-
-	return !xa_empty(&table->devices);
+	return table && !xa_empty(&table->devices);
 }
 
 static ssize_t sfnum_show(struct device *dev, struct device_attribute *attr, char *buf)