mlxsw: spectrum: acl: Implement delta for ERP

Allow ERP sharing for multiple mask. Do it by properly implementing
delta_create() objagg object. Use the computed delta info for inserting
rules in A-TCAM.

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>