TBF flow: unit test compilation error fix

The test failure was introduced by 9bbe1600cc02e1b538380393edb1dcdabe9247a2
"Fix Timing Advance handling": between patch build checking and patch
submission, a new section was added to TbfTest.cpp which also needs adjustment.

Tweaked-by: Neels Hofmeyr <nhofmeyr@sysmocom.de>
Change-Id: If077da5f21fd5cba54556f1dead05a1bc4ea5540
1 file changed