video: fbdev: udlfb: fix kobj_to_dev.cocci warnings

 Use kobj_to_dev() instead of container_of()

Generated by: scripts/coccinelle/api/kobj_to_dev.cocci

Cc: Denis Efremov <efremov@linux.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Cc: Bernie Thompson <bernie@plugable.com>
[b.zolnierkie: minor patch summary fixup]
[b.zolnierkie: removed "Fixes:" tag (not in upstream tree)]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/alpine.DEB.2.22.394.2008262252270.2522@hadrien