ASoC: cs42l42: Use PLL for SCLK > 12.288MHz

ASoC: cs42l42: Use PLL for SCLK > 12.288MHz

It isn't possible to switch MCLK between 12MHz and 24MHz rate groups
on-the-fly - this can only be done when cs42l42 is powered-down.

All "normal" SCLK rates use an MCLK in the 12MHz group, so change the
configs for SCLK > 12.288 MHz to use the PLL to generate an MCLK in
the 12MHz group.

As this means MCLK_DIV is always 0 it can be removed from the pll
configuration setup.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20211015133619.4698-12-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>