drm/amdgpu: 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: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231204090852.1650-3-tzimmermann@suse.de

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -92,7 +92,6 @@
 #include <drm/drm_vblank.h>
 #include <drm/drm_audio_component.h>
 #include <drm/drm_gem_atomic_helper.h>
-#include <drm/drm_plane_helper.h>
 
 #include <acpi/video.h>