ASoC: cpcap: Implement .set_bias_level

With VAUDIO regulator being always on, we have to put it in low-power mode
when codec is not in use to decrease power usage.

Do so by implementing driver .set_bias_level callback.

Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Link: https://patch.msgid.link/20250122164129.807247-3-ivo.g.dimitrov.75@gmail.com


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