net/mlx5: Not returning mlx5_link_info table when speed is unknown

Because mlx5e_link_info and mlx5e_ext_link_info have holes
e.g. Azure mlx5 reports PTYS 19. Do not return it unless speed
is retrieved successfully.

Fixes: 65a5d35 ("net/mlx5: Refactor link speed handling with mlx5_link_info struct")
Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Li Tian <litian@redhat.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20250910003732.5973-1-litian@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: litian1992

drivers/net/ethernet/mellanox/mlx5/core/port.c

@@ -1170,7 +1170,11 @@ const struct mlx5_link_info *mlx5_port_ptys2info(struct mlx5_core_dev *mdev,
 	mlx5e_port_get_link_mode_info_arr(mdev, &table, &max_size,
 					  force_legacy);
 	i = find_first_bit(&temp, max_size);
-	if (i < max_size)
+
+	/* mlx5e_link_info has holes. Check speed
+	 * is not zero as indication of one.
+	 */
+	if (i < max_size && table[i].speed)
 		return &table[i];
 
 	return NULL;