hevc: Reject impossible dependent tile

The tile 0 cannot depend on a previous one.
Prevent an out of array bound load in ff_hevc_cabac_init().

Fixes: asan_heap-oob_e3a924_1630_DBLK_A_MAIN10_VIXS_2.bit
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

Reviewed-by: Guillaume Martres <smarter@ubuntu.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
