[CLEANUP] #5199 Use $GLOBALS['TCA'] instead of $TCA

Change-Id: I386cee5c8a8688a285e117a52d99e1864116846b
Reviewed-on: http://review.typo3.org/35298
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>