ASoC: qcom: apq8016-sbc: Add support to multi codec.

This patch adds support to multi codec, as the msm8916 codec is now
split into two codecs, Analog and Digital.

Also update the bindings and example to show that the card supports
multicodec.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>