drm/i915: Turn force VDD back off when panel running in intel_dp_dpms

The VDD force bit is turned on before touching the panel, but if it
was enabled, there was no call to turn it back off. Add a call.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -1088,7 +1088,8 @@ intel_dp_dpms(struct drm_encoder *encoder, int mode)
 			ironlake_edp_panel_on(intel_dp);
 			ironlake_edp_panel_vdd_off(intel_dp);
 			intel_dp_complete_link_train(intel_dp);
-		}
+		} else
+			ironlake_edp_panel_vdd_off(intel_dp);
 		if (is_edp(intel_dp))
 			ironlake_edp_backlight_on(dev);
 	}