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