ASoC: msm8916: Add msm8916-wcd codec driver

ASoC: msm8916: Add msm8916-wcd codec driver

This patch adds support to msm8916-wcd codec.

msm8916-wcd codec is found in Qualcomm msm8916 and apq8016 processors.
This codec IP is split in to two parts(Digital & Analog), Analog part
is integrated in to PMIC PM8916 and the digital part is integrated into
Application processor. Register access to the analog part is done via
SPMI interface to PMIC, and registers on the Application processor are
memory mapped. Data transfer between Analog and Digital Die is done via
a internal bus called PDM.

This codec support includes:
 - 3 Microphones: Primary Mic(Handset mic), Headset Mic and Secondary Mic.
 - 2 Digital Microphones.
 - 2 Mic Bias Circuits.
 - Earpiece
 - Headset
 - Loud Speaker.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>