drm: Define enum mode_set_atomic in drm_modeset_helper_tables.h

Define enum mode_set_atomic next to the only interface that uses
the type. This will allow for removing several include statements
for drm_fb_helper.h. No functional changes.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20230111130206.29974-7-tzimmermann@suse.de

include/drm/drm_fb_helper.h

@@ -37,11 +37,6 @@ struct drm_fb_helper;
 
 #include <drm/drm_client.h>
 
-enum mode_set_atomic {
-	LEAVE_ATOMIC_MODE_SET,
-	ENTER_ATOMIC_MODE_SET,
-};
-
 /**
  * struct drm_fb_helper_surface_size - describes fbdev size and scanout surface size
  * @fb_width: fbdev width

include/drm/drm_modeset_helper_vtables.h

@@ -48,10 +48,14 @@
  * To make this clear all the helper vtables are pulled together in this location here.
  */
 
-enum mode_set_atomic;
 struct drm_writeback_connector;
 struct drm_writeback_job;
 
+enum mode_set_atomic {
+	LEAVE_ATOMIC_MODE_SET,
+	ENTER_ATOMIC_MODE_SET,
+};
+
 /**
  * struct drm_crtc_helper_funcs - helper operations for CRTCs
  *