drm/edid: Clear old audio latency values before parsing the new EDID

drm/edid: Clear old audio latency values before parsing the new EDID

Clear out stale audio latency information (potentially from a previous
EDID) before constructing the ELD from the EDID.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1475070703-6435-2-git-send-email-ville.syrjala@linux.intel.com