OMAPDSS: hdmi: Remove most of OMAP[45]_DSS_HDMI_AUDIO ifdefs

It does not waste too many bytes to compile all audio related core
functions always in with HDMI support. It should help readability and
in keeping the audio code in working shape. Leave the options just for
disabling and enabling the functionality in hdmi[45].c.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>