[TASK] Removed loadTCA calls

Since TYPO3 CMS 6.1, it is no longer necessary to
call loadTCA() when extending existing TCA structures.

Resolves: #55059
Releases: 0.6
Change-Id: Ieb4e1c4b8e1913fe2b06ba24b57537df64744d5c
Reviewed-on: https://review.typo3.org/26885
Reviewed-by: Francois Suter
Tested-by: Francois Suter