ASoC: Enable the RPi simple soundcard driver

Switch the following soundcards to use the RPi simple soundcard driver
and remove the dedicate driver implementations.

* ADAU1977 ADC
* Google VoiceHat
* HifiBerry AMP
* HifiBerry DAC
* RPI DAC

There is no impact on defconfig or codec configuration. Instead of
enabling the config to build the dedicated driver the menuconfig entries
now just select SND_RPI_SIMPLE_SOUNDCARD.

Signed-off-by: Tim Gover <tim.gover@raspberrypi.org>