mlxsw: spectrum_acl: Track ingress and egress block bindings

Count the number of ingress and egress block bindings. Use the egress
counter in "is_egress_bound" helper. Add couple of helpers to check
ingress and mixed bound.

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>