wifi: wireless: deny wireless extensions on MLO-capable devices

wifi: wireless: deny wireless extensions on MLO-capable devices

These are WiFi 7 devices that will be introduced into the market
in 2023, with new drivers. Wireless extensions haven't been in
real development since 2006. Since wireless has evolved a lot,
and continues to evolve significantly with Multi-Link Operation,
there's really no good way to still support wireless extensions
for devices that do MLO.

Stop supporting wireless extensions for new devices. We don't
consider this a regression since no such devices (apart from
hwsim) exist yet.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230118105152.45f85078a1e0.Ib9eabc2ec5bf6b0244e4d973e93baaa3d8c91bd8@changeid