ASoC: kirkwood: allow smaller audio periods and smaller number of periods

There is no hardware restriction requiring a minimum of 8 periods, or
a minimum of 2048 bytes in a period.  Let's drop these values so that
userspace has more flexibility in choosing these parameters.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/kirkwood/kirkwood.h

@@ -124,9 +124,9 @@
 
 /* Theses values come from the marvell alsa driver */
 /* need to find where they come from               */
-#define KIRKWOOD_SND_MIN_PERIODS		8
+#define KIRKWOOD_SND_MIN_PERIODS		2
 #define KIRKWOOD_SND_MAX_PERIODS		16
-#define KIRKWOOD_SND_MIN_PERIOD_BYTES		0x800
+#define KIRKWOOD_SND_MIN_PERIOD_BYTES		256
 #define KIRKWOOD_SND_MAX_PERIOD_BYTES		0x8000
 #define KIRKWOOD_SND_MAX_BUFFER_BYTES		(KIRKWOOD_SND_MAX_PERIOD_BYTES \
 						 * KIRKWOOD_SND_MAX_PERIODS)