drm: rcar-du: Remove unused prototypes

The CRTC suspend and resume functions have been replaced, but the
prototypes were not removed.

Remove the redundant definitions.
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_du_crtc.h

@@ -102,8 +102,6 @@ enum rcar_du_output {
 
 int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int swindex,
 			unsigned int hwindex);
-void rcar_du_crtc_suspend(struct rcar_du_crtc *rcrtc);
-void rcar_du_crtc_resume(struct rcar_du_crtc *rcrtc);
 
 void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc);