hevc: fix wpp threading deadlock.

Fixes ticket 4258.

libavcodec/hevc.c

@@ -2401,6 +2401,8 @@ static int hls_decode_entry_wpp(AVCodecContext *avctxt, void *input_ctb_row, int
 
         if (more_data < 0) {
             s->tab_slice_address[ctb_addr_rs] = -1;
+            avpriv_atomic_int_set(&s1->wpp_err,  1);
+            ff_thread_report_progress2(s->avctx, ctb_row ,thread, SHIFT_CTB_WPP);
             return more_data;
         }