ASoC: madera: Add channel numbers to AIFs

Set the channel number on each AIF widget to allow unused channels not
to be powered up across AIFs.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20200728144141.16104-1-ckeepax@opensource.cirrus.com


Signed-off-by: Mark Brown <broonie@kernel.org>