drm/omapdrm: Fix console by implementing fb_dirty

The framebuffer console stopped updating with commit f231af49
("drm/fb-helper: Disconnect damage worker from update logic").

Let's fix the issue by implementing fb_dirty similar to what was done
with commit 039a72ce ("drm/i915/fbdev: Implement fb_dirty for intel
custom fb helper").

Fixes: f231af49 ("drm/fb-helper: Disconnect damage worker from update logic")
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240228063540.4444-2-tony@atomide.com

drivers/gpu/drm/omapdrm/omap_fbdev.c

@@ -238,8 +238,20 @@ static int omap_fbdev_create(struct drm_fb_helper *helper,
 	return ret;
 }
 
+static int omap_fbdev_dirty(struct drm_fb_helper *helper, struct drm_clip_rect *clip)
+{
+	if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
+		return 0;
+
+	if (helper->fb->funcs->dirty)
+		return helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
+
+	return 0;
+}
+
 static const struct drm_fb_helper_funcs omap_fb_helper_funcs = {
 	.fb_probe = omap_fbdev_create,
+	.fb_dirty = omap_fbdev_dirty,
 };
 
 static struct drm_fb_helper *get_fb(struct fb_info *fbi)