net/mlx5e: Branch according to classified tunnel type

Currently the tunnel offloading encap/decap methods assumes that VXLAN
is the sole tunneling protocol. Lay the infrastructure for supporting
multiple tunneling protocols by branching according to the tunnel
net device kind.

Encap filters tunnel type is determined according to the egress/mirred
net device. Decap filters classify the tunnel type according to the
filter's ingress net device kind.

Distinguish between the tunnel type as defined by the SW model and
the FW reformat type that specifies the HW operation being made.

Signed-off-by: Oz Shlomo <ozsh@mellanox.com>
Reviewed-by: Eli Britstein <elibr@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>