wifi: mac80211: unify link STA removal in vif link removal

wifi: mac80211: unify link STA removal in vif link removal

There are multiple cases where interface links are removed
and the station links need to be removed with them, e.g.
in mlme.c we have both received and transmitted multi-link
reconfiguration, doing the two things in different order,
the former deleting STA links when the vif link change may
still fail.

It's also not clear that userspace (hostapd) couldn't, at
least in theory, remove a link from an interface without
removing the station links first, or even leave stations
that aren't MLO-capable, using that link.

Unify this code into ieee80211_vif_update_links() so that
it always happens, always happens in the right order and
is transactional (i.e. failures are handled correctly.)

Link: https://patch.msgid.link/20260529102644.c352f73a4658.I7219a5d72dab2abcecea9b5c52e7eb7a50e68d9b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>