drm: renesas: shmobile: Cleanup encoder

Most unused callbacks can be NULL pointers these days.
Drop a bunch of empty encoder callbacks.
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/04f186573e1df90ecc051272f3d1cbe564c3469b.1694767209.git.geert+renesas@glider.be

drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c

@@ -534,11 +534,6 @@ int shmob_drm_crtc_create(struct shmob_drm_device *sdev)
  * Encoder
  */
 
-static void shmob_drm_encoder_dpms(struct drm_encoder *encoder, int mode)
-{
-	/* No-op, everything is handled in the CRTC code. */
-}
-
 static bool shmob_drm_encoder_mode_fixup(struct drm_encoder *encoder,
 					 const struct drm_display_mode *mode,
 					 struct drm_display_mode *adjusted_mode)
@@ -561,29 +556,8 @@ static bool shmob_drm_encoder_mode_fixup(struct drm_encoder *encoder,
 	return true;
 }
 
-static void shmob_drm_encoder_mode_prepare(struct drm_encoder *encoder)
-{
-	/* No-op, everything is handled in the CRTC code. */
-}
-
-static void shmob_drm_encoder_mode_set(struct drm_encoder *encoder,
-				       struct drm_display_mode *mode,
-				       struct drm_display_mode *adjusted_mode)
-{
-	/* No-op, everything is handled in the CRTC code. */
-}
-
-static void shmob_drm_encoder_mode_commit(struct drm_encoder *encoder)
-{
-	/* No-op, everything is handled in the CRTC code. */
-}
-
 static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
-	.dpms = shmob_drm_encoder_dpms,
 	.mode_fixup = shmob_drm_encoder_mode_fixup,
-	.prepare = shmob_drm_encoder_mode_prepare,
-	.commit = shmob_drm_encoder_mode_commit,
-	.mode_set = shmob_drm_encoder_mode_set,
 };
 
 int shmob_drm_encoder_create(struct shmob_drm_device *sdev)