avformat/aiffenc: Remove wrong and redundant check

The check "if (!pb->seekable & AVIO_SEEKABLE_NORMAL)" is wrong, because
! has higher precendence than &. But it is also redundant, because this
part of the code is only ever reached when the AVIO_SEEKABLE_NORMAL flag
is set for pb. So simply remove the check.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Reviewed-by: Matthieu Bouron <matthieu.bouron@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/aiffenc.c

@@ -49,9 +49,6 @@ static int put_id3v2_tags(AVFormatContext *s, AIFFOutputContext *aiff)
     AVIOContext *pb = s->pb;
     AVPacketList *pict_list = aiff->pict_list;
 
-    if (!pb->seekable & AVIO_SEEKABLE_NORMAL)
-        return 0;
-
     if (!s->metadata && !aiff->pict_list)
         return 0;