ARM: dts: add audio support for APQ8084 alt MTP

The alternate MTP with APQ8084 and MDM9x35 uses MI2S for
connecting the MDM and the codec.
Add device tree support for audio on APQ8084 alternate
MTP devices, which uses new power grids.

Change-Id: I24f915d9e962768d43a0dfee4fd336c8c4428693
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>