mpegts: do not return from ff_mpegts_parse_packet() after having seen the first PMT

It prevents leaving the AVPacket uninitialized.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit bc38e837

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

libavformat/mpegts.c

@@ -1862,10 +1862,8 @@ int ff_mpegts_parse_packet(MpegTSContext *ts, AVPacket *pkt,
 
     len1 = len;
     ts->pkt = pkt;
-    ts->stop_parse = 0;
     for(;;) {
-        if (ts->stop_parse>0)
-            break;
+        ts->stop_parse = 0;
         if (len < TS_PACKET_SIZE)
             return -1;
         if (buf[0] != 0x47) {
@@ -1875,6 +1873,8 @@ int ff_mpegts_parse_packet(MpegTSContext *ts, AVPacket *pkt,
             handle_packet(ts, buf);
             buf += TS_PACKET_SIZE;
             len -= TS_PACKET_SIZE;
+            if (ts->stop_parse == 1)
+                break;
         }
     }
     return len1 - len;