Both gmch and pch detection routines used the exact same routine for
eDP, so de-duplicate.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: N: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>