Clean up the handling of bitclock frequency by keeping all the logic
in cs42l42_pcm_hw_params(), which then simply passes the frequency as
an argument to cs42l42_pll_config().

The previous code had become clunky as a legacy of earlier versions of
the clock handling. The logic was split across cs42l42_pcm_hw_params()
and cs42l42_pll_config(), with the params-derived bclk stashed in
struct cs42l42_private only to pass it to cs42l42_pll_config().
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20220915094444.11434-3-povik+lin@cutebit.orgSigned-off-by: Mark Brown <broonie@kernel.org>