mlxsw: spectrum_acl: Adapt ACL configuration to new firmware versions

The driver currently creates empty ACL groups, binds them to the
requested port and then fills them with actual ACLs that point to TCAM
regions.

However, empty ACL groups are considered invalid and upcoming firmware
versions are going to forbid their binding.

Work around this limitation by only performing the binding after the
first ACL was added to the group.

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>