wifi: mac80211: simplify ieee80211_sta_rx_bw_to_chan_width()

wifi: mac80211: simplify ieee80211_sta_rx_bw_to_chan_width()

This function is only called for at least HT capable stations,
so doesn't need to differentiate 20/20_NOHT. Also, the check
for VHT 160 MHz support is wrong, since a station could have
support for both and the AP is using 80+80, but nothing cares
anyway, so we don't need that.

Simplify the function and move it to util.c since it now no
longer is related to VHT, and also doesn't need a station.

Also use the new function in ieee80211_get_sta_bw() for the
chandef calculations, it just needs to handle the 20/20-noht
separately; while at it fix that to handle HE stations.

Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20260415144514.7b0be1059436.I573add4e3ed68b15f8b45122d053ac523afe4025@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>