wcn36xx: Set PHY into correct mode for 80MHz channel width

For the 80MHz channel we need to set the PHY mode to one of four PHY modes
that span the 80MHz range.

This patch latches the hw_value PHY field previously defined for 5GHz
channels directly to the parameter passed to the firmware.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200910150708.2179043-6-bryan.odonoghue@linaro.org