Six channels are unsupported by 8852b, so mask them out to prevent to
access undefined registers in this chip.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220927062611.30484-3-pkshih@realtek.com