Set right channel frequencies in VHT160 mode according to the VHT160
interoperability workaround added as part of IEEE Std 802.11™-2016 in
"Table 9-252—VHT Operation Information subfields", band_center_freq2
corresponds to CCFS1 in Table 9-253. Previous implementation
(band_center_freq2 = 0 for VHT160) is only deprecated.

Enable VHT80+80 mode and set the proper peer RX nss value for VHT160 and
VHT80+80 mode.

Based on patches by Sebastian Gottschall:

https://lkml.kernel.org/r/20180704095444.662-1-s.gottschall@dd-wrt.com

https://lkml.kernel.org/r/20180704120519.6479-1-s.gottschall@dd-wrt.com

Tested: qca9984 with firmware ver 10.4-3.10-00047
Co-developed-by: NSebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: NSebastian Gottschall <s.gottschall@dd-wrt.com>
Co-developed-by: NRick Wu <rwu@codeaurora.org>
Signed-off-by: NRick Wu <rwu@codeaurora.org>
Signed-off-by: NLei Wang <leiwa@codeaurora.org>
Signed-off-by: NSowmiya Sree Elavalagan <ssreeela@codeaurora.org>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1585574792-719-1-git-send-email-ssreeela@codeaurora.org