drm/fbdev-shmem: Clean up deferred I/O

Call fb_deferred_io_cleanup() upon destroying the framebuffer
device. Releases the internal memory.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 150f431a ("drm/fbdev: Add fbdev-shmem")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240507152329.3085-1-tzimmermann@suse.de

drivers/gpu/drm/drm_fbdev_shmem.c

@@ -60,6 +60,7 @@ static void drm_fbdev_shmem_fb_destroy(struct fb_info *info)
 	if (!fb_helper->dev)
 		return;
 
+	fb_deferred_io_cleanup(info);
 	drm_fb_helper_fini(fb_helper);
 
 	drm_client_buffer_vunmap(fb_helper->buffer);