wifi: nl80211: completely disable per-link stats for now

After commit 8cc71fc3 ("wifi: cfg80211: Fix "no buffer
space available" error in nl80211_get_station() for MLO"),
the per-link data is only included in station dumps, where
the size limit is somewhat less of an issue. However, it's
still an issue, depending on how many links a station has
and how much per-link data there is. Thus, for now, disable
per-link statistics entirely.

A complete fix will need to take this into account, make it
opt-in by userspace, and change the dump format to be able
to split a single station's data across multiple netlink
dump messages, which all together is too much development
for a fix.

Fixes: 82d7f841 ("wifi: cfg80211: extend to embed link level statistics in NL message")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>