net/mlx5: fix build with clang 14

net/mlx5: fix build with clang 14

Use fgets instead of fscanf to resolve the following warning
reported by clang 14.0.0 in Fedora 37 (Rawhide):

drivers/net/mlx5/linux/mlx5_ethdev_os.c:1137:52: error:
  'fscanf' may overflow; destination buffer in argument 3 has size 16,
  but the corresponding specifier may require size 17
  [-Werror,-Wfortify-source]
  ret = fscanf(file, "%" RTE_STR(IF_NAMESIZE) "s", port_name);

Fixes: 63d1db710fbc ("net/mlx5: fix unlimited parsing of switch info")
Cc: stable@dpdk.org
Signed-off-by: Ali Alnubani <alialnu@nvidia.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>