Notifiations like mode change, hot plug and edid to
the audio driver are added. This is inturn used by the
audio driver for its functionality.

A new interface file capturing the notifications needed by the
audio driver is added
Signed-off-by: NPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: NJerome Anand <jerome.anand@intel.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>