truemotion2: clear the token array if its initialization fails.

Fixes use of uninitialized and half initialized values, which
can occur on several error pathes

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
truemotion2: use av_mallocz()

Fixes use of uninitialized values.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>