drm: rcar-du: lvds: Avoid duplication of clock clamp code

Replace the duplicate code by a single central function.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.h b/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.h
index 9a6001c..dfdba74 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.h
@@ -30,6 +30,8 @@
 int rcar_du_lvdsenc_init(struct rcar_du_device *rcdu);
 int rcar_du_lvdsenc_enable(struct rcar_du_lvdsenc *lvds,
 			   struct drm_crtc *crtc, bool enable);
+void rcar_du_lvdsenc_atomic_check(struct rcar_du_lvdsenc *lvds,
+				  struct drm_display_mode *mode);
 #else
 static inline int rcar_du_lvdsenc_init(struct rcar_du_device *rcdu)
 {
@@ -40,6 +42,10 @@
 {
 	return 0;
 }
+static inline void rcar_du_lvdsenc_atomic_check(struct rcar_du_lvdsenc *lvds,
+						struct drm_display_mode *mode)
+{
+}
 #endif
 
 #endif /* __RCAR_DU_LVDSENC_H__ */