[BUGFIX] Bring back tt_content layout field

Change-Id: I3b800bfa1b4eb90ef654d772fcf0b797db8d722b
Resolves: #61096
Reviewed-on: http://review.typo3.org/34729
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>