OMAP4: DSS2: HDMI: Add functionality for audio configuration

Add functionality for relevant audio configuration. Functions to
configure the audio FIFO and DMA as well as functions for the audio
core and Audio Info frame are included. This functionality is to
be used by the ASoC HDMI audio codec.

Signed-off-by: Ricardo Neri <ricardo.neri@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>