net/mlx5e: Add helper for encap_info_equal for tunnels with options

For tunnels with options, eg, geneve and vxlan with gbp, they share the
same way to compare the headers and options. Extract the code as a common
function for them.

Signed-off-by: Gavin Li <gavinl@nvidia.com>
Reviewed-by: Gavi Teitz <gavi@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Acked-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>