net/mlx5e: CT: Use mapping for zone restore register

Use a single byte mapping for zone restore register (zone matching
remains 16 bit).

This makes room for using the freed 8 bits on register C1 for
mapping more tunnels and tunnel options.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>