qtnfmac: pass channel definition to WiFi card on START_AP command

Introduce "channel definition" TLV containing full channel
description (center frequence for both segments + BW) and pass it to
wireless card in a payload to START_AP command.

Signed-off-by: Igor Mitsyanko <igor.mitsyanko.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>