ALSA: seq: correctly detect input buffer overflow

snd_seq_event_dup returns -ENOMEM in some buffer-full conditions,
but usually returns -EAGAIN. Make -EAGAIN trigger the overflow
condition in snd_seq_fifo_event_in so that the fifo is cleared
and -ENOSPC is returned to userspace as stated in the alsa-lib docs.

Signed-off-by: Adam Goode <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

sound/core/seq/seq_fifo.c

···
 	snd_use_lock_use(&f->use_lock);
 	err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */
 	if (err < 0) {
-		if (err == -ENOMEM)
+		if ((err == -ENOMEM) || (err == -EAGAIN))
 			atomic_inc(&f->overflow);
 		snd_use_lock_free(&f->use_lock);
 		return err;