ASoC: msm8916-wcd-analog: Add earpiece

PM8916 supports an earpiece as another (small) speaker.
The earpiece is routed through RX MIX1 similarly to
the headphones, except that RDAC2 MUX is set to RX1.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20191020153007.206070-2-stephan@gerhold.net


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