mlxsw: spectrum_acl: Support rule creation without action creation

Up until now, when ACL rule was created its action was created with it.
It suits well for tc flower where ACL rule always needs an action, however
it does not suit multicast router, where the action is created prior to
setting a route, which in Spectrum-2 is actually an ACL rule.

Add support for rule creation without action creation. Do it by adding
afa_block argument to mlxsw_sp_acl_rule_create, which if NULL then an
action would be created, also add an indication within struct
mlxsw_sp_acl_rule_info that tells if the action should be destroyed when
the rule is destroyed.

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