brcmfmac: add 160MHz in chandef_to_chanspec()

The function chandef_to_chanspec() was not handling 160MHz bandwidth
resulting in wrong encoding of the channel. That resulting in firmware
rejecting the provided channel specification.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>