ALSA: pcm: Make constraints lists const

They aren't modified by the core so the drivers can declare them const.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/pcm.h

@@ -810,7 +810,7 @@ int snd_pcm_hw_constraint_integer(struct snd_pcm_runtime *runtime, snd_pcm_hw_pa
 int snd_pcm_hw_constraint_list(struct snd_pcm_runtime *runtime, 
 			       unsigned int cond,
 			       snd_pcm_hw_param_t var,
-			       struct snd_pcm_hw_constraint_list *l);
+			       const struct snd_pcm_hw_constraint_list *l);
 int snd_pcm_hw_constraint_ratnums(struct snd_pcm_runtime *runtime, 
 				  unsigned int cond,
 				  snd_pcm_hw_param_t var,

sound/core/pcm_lib.c

@@ -1250,10 +1250,10 @@ static int snd_pcm_hw_rule_list(struct snd_pcm_hw_params *params,
 int snd_pcm_hw_constraint_list(struct snd_pcm_runtime *runtime,
 			       unsigned int cond,
 			       snd_pcm_hw_param_t var,
-			       struct snd_pcm_hw_constraint_list *l)
+			       const struct snd_pcm_hw_constraint_list *l)
 {
 	return snd_pcm_hw_rule_add(runtime, cond, var,
-				   snd_pcm_hw_rule_list, l,
+				   snd_pcm_hw_rule_list, (void *)l,
 				   var, -1);
 }