ASoC: imx-ssi: increase minimum periods to 4

Currently the notification of elapsed periods is not very exact.
Increase minimum periods to 4 as suggested by Liam Girdwood.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/imx/imx-pcm-fiq.c

@@ -174,7 +174,7 @@ static struct snd_pcm_hardware snd_imx_hardware = {
 	.buffer_bytes_max = IMX_SSI_DMABUF_SIZE,
 	.period_bytes_min = 128,
 	.period_bytes_max = 16 * 1024,
-	.periods_min = 2,
+	.periods_min = 4,
 	.periods_max = 255,
 	.fifo_size = 0,
 };