[BUGFIX] Error when update mapping via module

When the TV backend module (Section: Page) gets used to update a
mapping an error gets thrown because of an not existing class.

Change-Id: I95fa7866dbb667f6b53d656026668ca6070dfa2f
Resolves: #60471
Releases: 2.0.0
Reviewed-on: https://review.typo3.org/31724
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>