drm/fb-helper: Set damage-clip area in helper

Set the damage area in the new helper drm_fb_helper_add_damage_clip().
It can now be updated without scheduling the damage worker. This change
will help to remove the damage worker entirely. No functional changes.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20221115115819.23088-2-tzimmermann@suse.de

drivers/gpu/drm/drm_fb_helper.c

@@ -576,7 +576,7 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
 }
 EXPORT_SYMBOL(drm_fb_helper_fini);
 
-static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
+static void drm_fb_helper_add_damage_clip(struct drm_fb_helper *helper, u32 x, u32 y,
 					  u32 width, u32 height)
 {
 	struct drm_clip_rect *clip = &helper->damage_clip;
@@ -588,6 +588,12 @@ static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
 	clip->x2 = max_t(u32, clip->x2, x + width);
 	clip->y2 = max_t(u32, clip->y2, y + height);
 	spin_unlock_irqrestore(&helper->damage_lock, flags);
+}
+
+static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
+				 u32 width, u32 height)
+{
+	drm_fb_helper_add_damage_clip(helper, x, y, width, height);
 
 	schedule_work(&helper->damage_work);
 }