ASoC: msm: Add support to query the channel map info

Implement method to get the channel map information from the
user space.
Remove the global variables in pcm driver to store the channel
map in the platform driver. This is needed to support multiple
instances of pcm driver for different pcm streams.

Change-Id: I9035db4e52f39b9d612312bafab4d22a28937f4b
Signed-off-by: Subhash Chandra Bose Naripeddy <snariped@codeaurora.org>