ASoC: twl6040: Constify rate constraints

The rate constraints in this driver are shared between all device instances. It
should not be (and is not) modified at runtime, so make them const.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/codecs/twl6040.c b/sound/soc/codecs/twl6040.c
index 0afe8be..cb642c9 100644
--- a/sound/soc/codecs/twl6040.c
+++ b/sound/soc/codecs/twl6040.c
@@ -81,7 +81,7 @@
 };
 
 /* set of rates for each pll: low-power and high-performance */
-static unsigned int lp_rates[] = {
+static const unsigned int lp_rates[] = {
 	8000,
 	11250,
 	16000,
@@ -93,7 +93,7 @@
 	96000,
 };
 
-static unsigned int hp_rates[] = {
+static const unsigned int hp_rates[] = {
 	8000,
 	16000,
 	32000,
@@ -101,7 +101,7 @@
 	96000,
 };
 
-static struct snd_pcm_hw_constraint_list sysclk_constraints[] = {
+static const struct snd_pcm_hw_constraint_list sysclk_constraints[] = {
 	{ .count = ARRAY_SIZE(lp_rates), .list = lp_rates, },
 	{ .count = ARRAY_SIZE(hp_rates), .list = hp_rates, },
 };