[BUGFIX] Max items reached message always shown

Refactoring this part of the code wasn't done correctly.
Fix this by checking if max items is reached and then show the
message.

Releases: 2.0.0
Change-Id: If038b0a4aeb06ab108d7990a41809ca005da2b60
Reviewed-on: https://review.typo3.org/31582
Reviewed-by: Alexander Schnitzler <typo3@alexanderschnitzler.de>
Tested-by: Alexander Schnitzler <typo3@alexanderschnitzler.de>