ALSA: ctxfi - Set periods_min to 2

Set 2 to minimal periods of playback pcm setups, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ctxfi/ctpcm.c b/sound/pci/ctxfi/ctpcm.c
index 32b742d..a0bd31c 100644
--- a/sound/pci/ctxfi/ctpcm.c
+++ b/sound/pci/ctxfi/ctpcm.c
@@ -40,7 +40,7 @@
 	.buffer_bytes_max	= (128*1024),
 	.period_bytes_min	= (64),
 	.period_bytes_max	= (128*1024),
-	.periods_min		= 1,
+	.periods_min		= 2,
 	.periods_max		= 1024,
 	.fifo_size		= 0,
 };
@@ -62,7 +62,7 @@
 	.buffer_bytes_max	= (128*1024),
 	.period_bytes_min	= (64),
 	.period_bytes_max	= (128*1024),
-	.periods_min		= 1,
+	.periods_min		= 2,
 	.periods_max		= 1024,
 	.fifo_size		= 0,
 };