ASoC: codecs: msm8916-wcd-analog: clean parse_dt()

Move the code which is not parsing dt from pm8916_wcd_analog_parse_dt()
to make it clear to reader.

No functional changes done.

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