mlxsw: spectrum_acl: Split TCAM group structure into two

Make the existing group structure to contain fields needed for HW region
list manipulations. Move the rest of the fields into new vgroup struct.
This makes layering cleaner as the vgroup struct is on higher level than
low-level group struct. Also, this makes it possible to introduce
fine-grained locking.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>