[BUGFIX] FAL viewhelper does not work in backend context

Finally I've copied the database call from original FileRepository. I forgot the sorting -.-
Sorry for the inconvenience.

Resolves: #60706
Change-Id: I269c5a8dcd362832dbe5251d8f0ba73c5744621b
Reviewed-on: http://review.typo3.org/32597
Reviewed-by: Armin Ruediger Vieweg <armin@v.ieweg.de>
Tested-by: Armin Ruediger Vieweg <armin@v.ieweg.de>