ASoC: sun4i-i2s: Move the channel configuration to a callback

The two main generations of our I2S controller require a slightly different
channel configuration, mostly because of a quite different register layout
and some additional registers being needed on the newer generation.

This used to be controlled through a bunch of booleans, however this proved
to be quite impractical, especially since a bunch of SoCs forgot to set
those parameters and therefore were broken from that point of view.

Fixes: 21faaea1 ("ASoC: sun4i-i2s: Add support for A83T")
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://lore.kernel.org/r/6414463de69584e8227fa495b13aa5f4798e1f0e.1566242458.git-series.maxime.ripard@bootlin.comSigned-off-by: Mark Brown <broonie@kernel.org>