ASoC: cs42l42: Remove duplicate control for WNF filter frequency

ASoC: cs42l42: Remove duplicate control for WNF filter frequency

The driver was defining two ALSA controls that both change the same
register field for the wind noise filter corner frequency. The filter
response has two corners, at different frequencies, and the duplicate
controls most likely were an attempt to be able to set the value using
either of the frequencies.

However, having two controls changing the same field can be problematic
and it is unnecessary. Both frequencies are related to each other so
setting one implies exactly what the other would be.

Removing a control affects user-side code, but there is currently no
known use of the removed control so it would be best to remove it now
before it becomes a problem.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 2c394ca79604 ("ASoC: Add support for CS42L42 codec")
Link: https://lore.kernel.org/r/20210803160834.9005-2-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>