ASoC: msm8998: add mixer controls for MI2S bit format

MI2S ports supports multiple bit formats for Rx and Tx paths.
Add new mixer controls for supporting bit format for Rx and
Tx paths of all 4 MI2S ports in MSM8998 target. The bit format
for the MI2S ports will be used to setup Backend DAI configuration
through fixup function.

Change-Id: I1b9d154c900c9f9cf12ae7b279dc41b61af15faa
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>