movenc: remove unneeded check

Fixes CID741417
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/movenc.c

@@ -2037,7 +2037,7 @@ static int mov_write_int8_metadata(AVFormatContext *s, AVIOContext *pb,
 
     if (!(t = av_dict_get(s->metadata, tag, NULL, 0)))
         return 0;
-    num = t ? atoi(t->value) : 0;
+    num = atoi(t->value);
 
     avio_wb32(pb, len+8);
     ffio_wfourcc(pb, name);