ASoC: dt-bindings: qcom: apq8016-sbc: Move to qcom,sm8250 DT schema

All the Qualcomm sound card drivers use the same common device tree
parsing code, so the allowed device tree nodes are almost the same
for all of them. Convert the qcom,apq8016-sbc-sndcard documentation
to a DT schema by adding it to the existing qcom,sm8250 schema.

The only speciality of qcom,apq8016-sbc-sndcard is that it has memory
resources for setting up an I/O mux. This can be handled using
a conditional if statement that only requires it for the apq8016-sbc
compatible.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211202145505.58852-4-stephan@gerhold.net
Signed-off-by: Mark Brown <broonie@kernel.org>