ASoC: codecs: msm8916-wcd: Fix supported formats

This codec is configurable for only 16 bit and 32 bit samples, so reflect
this in the supported formats also remove 24bit sample from supported list.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org