luci-mod-status: channel_analysis: detect 160 MHz capable AP

luci-mod-status: channel_analysis: detect 160 MHz capable AP

Implement a workaround to detect an 160MHz capable AP. It was introduced
in the mac80211 in 2016 with 802.11ac Wave 2. APs capable of 160 MHz are
detected by the shift of central frequencies. More detailed description
in the link [1]. Every AP I have seen presents support for 160 MHz in this way.

[1] https://github.com/torvalds/linux/commit/23665aaf9170ae6328cc4f68250c529a628af2ab
Fixes: #6262
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>