IB/mlx5: Replace tunnel mpls capability bits for tunnel_offloads

IB/mlx5: Replace tunnel mpls capability bits for tunnel_offloads

Until now the flex parser capability was used in ib_query_device() to
indicate tunnel_offloads_caps support for mpls_over_gre/mpls_over_udp.

Newer devices and firmware will have configurations with the flexparser
but without mpls support.

Testing for the flex parser capability was a mistake, the tunnel_stateless
capability was intended for detecting mpls and was introduced at the same
time as the flex parser capability.

Otherwise userspace will be incorrectly informed that a future device
supports MPLS when it does not.

Link: https://lore.kernel.org/r/20200305123841.196086-1-leon@kernel.org
Cc: <stable@vger.kernel.org> # 4.17
Fixes: e818e255a58d ("IB/mlx5: Expose MPLS related tunneling offloads")
Signed-off-by: Alex Vesker <valex@mellanox.com>
Reviewed-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>