ASoC: msm: enhance MI2S CPU driver for bi-directional support

MI2S block has 4 serial data lines. They can be configured to
either Rx or TX direction. Existing driver only supports uni-direction
data transfer. Instead of registering two CPU DAIs for Tx and Rx direction,
update CPU DAI driver to register bi-directional CPU DAIs as Tx and Rx
share same bit clock and word select. Channel min and max of DAI depends
on Rx and Tx serial data line configuration passed as platform data.

Change-Id: I327999a4b84252121f54f91bd6451eebde4919ca
Signed-off-by: Patrick Lai <plai@codeaurora.org>