ALSA: cs46xx: constify snd_kcontrol_new structures

Declare snd_kcontrol_new structures as const as they are only passed an
argument to the function snd_ctl_new1. This argument is of type const,
so snd_kcontrol_new structures having this property can be made const.
Done using Coccinelle:

@r disable optional_qualifier@
identifier x;
position p;
@@
static struct snd_kcontrol_new x@p={...};

@ok@
identifier r.x;
position p;
@@
snd_ctl_new1(&x@p,...)

@bad@
position p != {r.p,ok.p};
identifier r.x;
@@
x@p

@depends on !bad disable optional_qualifier@
identifier r.x;
@@
+const
struct snd_kcontrol_new x;

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/cs46xx/cs46xx_lib.c

@@ -2371,7 +2371,7 @@ static int snd_cs46xx_front_dup_put(struct snd_kcontrol *kcontrol,
 				    ucontrol->value.integer.value[0] ? 0 : 0x200);
 }
 
-static struct snd_kcontrol_new snd_cs46xx_front_dup_ctl = {
+static const struct snd_kcontrol_new snd_cs46xx_front_dup_ctl = {
 	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
 	.name = "Duplicate Front",
 	.info = snd_mixer_boolean_info,