wifi: iwlwifi: Don't use valid_links to iterate sta links

wifi: iwlwifi: Don't use valid_links to iterate sta links

This bitmap equals to zero when in a non-MLO mode, and then we won't
be iterating on any link. Use for_each_sta_active_link() instead, as
it handles also the case of non-MLO mode.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230514120631.f32a8c08730a.Ib02248cd0b7f2bc885f91005c3c110dd027f9dcd@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>