ASoC: rt5651: Only configure LDO voltage once at boot

Now that rt5651_set_bias_level(BIAS_OFF) no longer modifies the LDO
voltage selection bits, there is no need to set them each time we move
to standby. Instead configure them once at component-probe() time.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mark Brown <broonie@kernel.org>