IBX BSpec says we must specify 8bpc in TRANSCONF for both 8bpc
and 12bpc HDMI output. Do so.

v2: Pass intel_crtc to intel_pipe_has_type()
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChandra Konduru <Chandra.konduru@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>