ASoC: imx-audmix: remove cpu_mclk which is from cpu dai device

ASoC: imx-audmix: remove cpu_mclk which is from cpu dai device

When defer probe happens, there may be below error:

platform 59820000.sai: Resources present before probing

The cpu_mclk clock is from the cpu dai device, if it is not released,
then the cpu dai device probe will fail for the second time.

The cpu_mclk is used to get rate for rate constraint, rate constraint
may be specific for each platform, which is not necessary for machine
driver, so remove it.

Fixes: b86ef5367761 ("ASoC: fsl: Add Audio Mixer machine driver")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://patch.msgid.link/20250213070518.547375-1-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>