ALSA: emu10k1 - Fix minimum periods for efx playback

EFX playback stream should have periods_min = 2 to avoid the buffer
position overflow (due to restrictions of the pcm-indirect helper).

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/emu10k1/emupcm.c

@@ -1736,7 +1736,7 @@ static struct snd_pcm_hardware snd_emu10k1_fx8010_playback =
 	.buffer_bytes_max =	(128*1024),
 	.period_bytes_min =	1024,
 	.period_bytes_max =	(128*1024),
-	.periods_min =		1,
+	.periods_min =		2,
 	.periods_max =		1024,
 	.fifo_size =		0,
 };