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>

libavcodec/hevc.c

@@ -1853,6 +1853,11 @@ static int hls_decode_entry(AVCodecContext *avctxt, void *isFilterThread)
     int y_ctb       = 0;
     int ctb_addr_ts = s->pps->ctb_addr_rs_to_ts[s->sh.slice_ctb_addr_rs];
 
+    if (!ctb_addr_ts && s->sh.dependent_slice_segment_flag) {
+        av_log(s->avctx, AV_LOG_ERROR, "Impossible initial tile.\n");
+        return AVERROR_INVALIDDATA;
+    }
+
     while (more_data && ctb_addr_ts < s->sps->ctb_size) {
         int ctb_addr_rs = s->pps->ctb_addr_ts_to_rs[ctb_addr_ts];