Revert "drm/i915: Ignore panel type from OpRegion on SKL"

This reverts commit bb10d4e.

Since commit c8ebfad ("drm/i915: Ignore OpRegion panel type except
on select machines") we ignore the OpRegion panel type except for
specific machines (handled via a DMI match), so having SKL explicitly
excluded from using the OpRegion panel type is redundant. So let's
remove the SKL check.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170308143334.21216-1-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_opregion.c

@@ -1070,16 +1070,5 @@ intel_opregion_get_panel_type(struct drm_i915_private *dev_priv)
 		return -ENODEV;
 	}
 
-	/*
-	 * FIXME On Dell XPS 13 9350 the OpRegion panel type (0) gives us
-	 * low vswing for eDP, whereas the VBT panel type (2) gives us normal
-	 * vswing instead. Low vswing results in some display flickers, so
-	 * let's simply ignore the OpRegion panel type on SKL for now.
-	 */
-	if (IS_SKYLAKE(dev_priv)) {
-		DRM_DEBUG_KMS("Ignoring OpRegion panel type (%d)\n", ret - 1);
-		return -ENODEV;
-	}
-
 	return ret - 1;
 }