net/mlx5: fix tunnel rules validation on VF representor

net/mlx5: fix tunnel rules validation on VF representor

MLX5 PMD implicitly adds vxlan_decap flow action to tunnel offload
match type rules. However, VXLAN decap action on VF representors is
not supported on MLX5 PMD hardware.

The patch rejects attempt to create tunnel offload flow rules on VF
representor.

Refer commit 9c4971e5231d ("net/mlx5: update VLAN and encap actions validation")

Fixes: 4ec6360de37d ("net/mlx5: implement tunnel offload")
Cc: stable@dpdk.org
Signed-off-by: Gregory Etelson <getelson@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>