drm/shmobile: Do not include <drm/drm_plane_helper.h>

Remove unnecessary include statements for <drm/drm_plane_helper.h>.
The file contains helpers for non-atomic code and should not be
required by most drivers. No functional changes.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patchwork.freedesktop.org/patch/msgid/20231204090852.1650-5-tzimmermann@suse.de

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

@@ -14,7 +14,6 @@
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_dma_helper.h>
-#include <drm/drm_plane_helper.h>
 
 #include "shmob_drm_drv.h"
 #include "shmob_drm_kms.h"