ASoC: qcom: make common.c as proper module

This patch converts common helper functions in to proper module
and also fixes below warning.

WARNING: sound/soc/qcom/snd-soc-sdm845: 'qcom_snd_parse_of' exported twice.
Previous export was in sound/soc/qcom/snd-soc-apq8096.ko

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