brstm: fix missing closing brace

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
(cherry picked from commit 1cb2331eca)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

libavformat/brstm.c

@@ -263,6 +263,7 @@ static int read_packet(AVFormatContext *s, AVPacket *pkt)
         if (!b->adpc) {
             av_log(s, AV_LOG_ERROR, "adpcm_thp requires ADPC chunk, but none was found.\n");
             return AVERROR_INVALIDDATA;
+        }
         if (!b->table) {
             b->table = av_mallocz(32 * codec->channels);
             if (!b->table)