ALSA: seq: oss: Fix running status after receiving sysex

This is a similar bug like the previous case for virmidi: the invalid
running status is kept after receiving a sysex message.

Again the fix is to clear the running status after handling the sysex.

Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/3b4a4e0f232b7afbaf0a843f63d0e538e3029bfd.camel@domdv.de
Link: https://lore.kernel.org/r/20200316090506.23966-3-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/seq/oss/seq_oss_midi.c

@@ -602,6 +602,7 @@ send_midi_event(struct seq_oss_devinfo *dp, struct snd_seq_event *ev, struct seq
 		len = snd_seq_oss_timer_start(dp->timer);
 	if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {
 		snd_seq_oss_readq_sysex(dp->readq, mdev->seq_device, ev);
+		snd_midi_event_reset_decode(mdev->coder);
 	} else {
 		len = snd_midi_event_decode(mdev->coder, msg, sizeof(msg), ev);
 		if (len > 0)