Expose new abilities when creating a packet reformat context.

The new types which can be created are:
MLX5_REFORMAT_TYPE_L2_TO_L2_TUNNEL: Ability to create generic encap
operation to be done by the HW.

MLX5_REFORMAT_TYPE_L3_TUNNEL_TO_L2: Ability to create generic decap
operation where the inner packet doesn't contain L2.

MLX5_REFORMAT_TYPE_L2_TO_L3_TUNNEL: Ability to create generic encap
operation to be done by the HW. The L2 of the original packet
is dropped.
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>