MT#61856 packet_sequencer_init: fix Coverity Scan defect

`packet_sequencer_init()` initializes
`packet_sequencer_t` sequence to -1 always.

So make sure to set `uint16_t` later not to
an underflowing value, which can potentially
set the `uint16_t` object type to some insanely
big value.

Fixes:

/daemon/codec.c: 1893 in __handler_func_sequencer()
1887            if (!seq) {
1888                    seq = g_slice_alloc0(sizeof(*seq));
1889                    packet_sequencer_init(seq, (GDestroyNotify) __transcode_packet_free);
1890                    g_hash_table_insert(ssrc_in_p->sequencers, mp->media_out, seq);
1891            }
1892
>>>     CID 1616503:  Integer handling issues  (INTEGER_OVERFLOW)
>>>     Expression "seq_ori", where "seq->seq" is known to be equal to -1, overflows the type of "seq_ori", which is type "uint16_t".
1893            uint16_t seq_ori = seq->seq;
1894            int seq_ret = packet_sequencer_insert(seq, &packet->p);
1895            if (seq_ret < 0) {
1896                    // dupe
1897                    int func_ret = 0;
1898                    if (packet->dup_func)

** CID 1616502:    (LOCK_EVASION)
/daemon/media_player.c: 487 in media_player_read_decoded_packet()
/daemon/media_player.c: 479 in media_player_read_decoded_packet()

Change-Id: Ifbd68021f17866aa9b7482b1bd42e2acf1c25dfa

daemon/codec.c

@@ -1890,7 +1890,7 @@ static int __handler_func_sequencer(struct media_packet *mp, struct transcode_pa
 		g_hash_table_insert(ssrc_in_p->sequencers, mp->media_out, seq);
 	}
 
-	uint16_t seq_ori = seq->seq;
+	uint16_t seq_ori = (seq->seq < 0) ? 0 : seq->seq;
 	int seq_ret = packet_sequencer_insert(seq, &packet->p);
 	if (seq_ret < 0) {
 		// dupe