fix tighten mode for wheezy

wheezy has multilib support, therfore tighten mode need to be fixed like
diet in 8c697255bd58437a1466b6d8cc46b7dbcd2a87ed.

Signed-off-by: Holger Dengler <dengler@linutronix.de>
Signed-off-by: Manuel Traut <manut@linutronix.de>