[BUGFIX] Fix fatal error in PermissionController

Make sure we deal with the correct view class before accessing
any members of it.

Resolves: #70728
Releases: master
Change-Id: I0cd8c2d775f7c0fd7202b314f1fc3ce3c71b58dc
Reviewed-on: http://review.typo3.org/44070


Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Tested-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Marcus Schwemer <ms@schwemer.de>
Tested-by: Marcus Schwemer <ms@schwemer.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>