ASoC: msm: Add support for configuring buffer size in multichannel driver

The buffer size is hardcoded in multichannel pcm driver. This results
in more pcm data in the driver for smaller sampling rates causing
Audio Video sync issues and old buffers played during seek operation.
Add support for configuring buffer size in multi channel pcm driver.
based on sample rate and channels.

Change-Id: I3db4a026b6627177168656769c3f2751dbb12391
Signed-off-by: Krishnankutty Kolathappilly <kkolat@codeaurora.org>