ASoC: tas2770: Drop conflicting set_bias_level power setting

The driver is setting the PWR_CTRL field in both the set_bias_level
callback and on DAPM events of the DAC widget (and also in the
mute_stream method). Drop the set_bias_level callback altogether as the
power setting it does is in conflict with the other code paths.

Fixes: 1a476abc

 ("tas2770: add tas2770 smart PA kernel driver")
Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20220808141246.5749-4-povik+lin@cutebit.org
Signed-off-by: Mark Brown <broonie@kernel.org>