ASoC: msm: Updated the period size of Multichannel driver

Upadate the multichannel driver period size to accomodate the
8 channels with 1536 bytes for each channel in HDMI IN use case.
Update the channels of wma according to the structure populated
by the HAL

Change-Id: Ia1ffd71b5f0535630d410fec64957caf7b48f187
Signed-off-by: Aviral Gupta <aviralg@codeaurora.org>