net/mlx5: fix validation of MLPS-in-GRE
net/mlx5: fix validation of MLPS-in-GRE

Multiple tunnel isn't allowed but MPLS over GRE should be accepted.

Fixes: 23c1d42c7138 ("net/mlx5: split flow validation to dedicated function")

Signed-off-by: Yongseok Koh <76b37c91816d73ef9cf709e3e83a68f2d162f1e2@mellanox.com>
Acked-by: Shahaf Shuler <59427d49da6f2b944fbf4cb5ee70ef3ac25f744f@mellanox.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk