ASoC: sdm845: 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 SDM845 target. The bit format
for the MI2S ports will be used to setup Backend DAI configuration
through fixup function.

Change-Id: Ia94f8a6c1d27782fd30b00f7df6918ede47dec58
Signed-off-by: Xiaoyu Ye <benyxy@codeaurora.org>