drm/i915/hdmi: implement get_hw_state

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index c39c705..4daa7e6 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -542,6 +542,8 @@
 
 extern void intel_enable_ddi(struct intel_encoder *encoder);
 extern void intel_disable_ddi(struct intel_encoder *encoder);
+extern bool intel_ddi_get_hw_state(struct intel_encoder *encoder,
+				   enum pipe *pipe);
 extern void intel_ddi_mode_set(struct drm_encoder *encoder,
 				struct drm_display_mode *mode,
 				struct drm_display_mode *adjusted_mode);