mlxsw: spectrum_acl: Reshuffle code around mlxsw_sp_acl_ruleset_create/destroy

In order to prepare for follow-up changes, make the bind/unbind helpers
very simple. That required move of ht insertion/removal and bind/unbind
calls into mlxsw_sp_acl_ruleset_create/destroy.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>