avcodec/wavpack: Remove always-false check

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
(cherry picked from commit d307aca184)

libavcodec/wavpack.c

@@ -1097,11 +1097,6 @@ static int wavpack_decode_block(AVCodecContext *avctx, int block_no,
     }
 
     s = wc->fdec[block_no];
-    if (!s) {
-        av_log(avctx, AV_LOG_ERROR, "Context for block %d is not present\n",
-               block_no);
-        return AVERROR_INVALIDDATA;
-    }
 
     memset(s->decorr, 0, MAX_TERMS * sizeof(Decorr));
     memset(s->ch, 0, sizeof(s->ch));