ALSA: pci: constify snd_kcontrol_new structures

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

@r1 disable optional_qualifier @
identifier i;
position p;
@@
static struct snd_kcontrol_new i@p = {...};

@ok1@
identifier r1.i;
position p;
expression e1;
@@
snd_ctl_new1(&i@p,e1)

@bad@
position p!={r1.p,ok1.p};
identifier r1.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r1.i;
@@
+const
struct snd_kcontrol_new i;

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/ens1370.c b/sound/pci/ens1370.c
index 164adad..5d10349 100644
--- a/sound/pci/ens1370.c
+++ b/sound/pci/ens1370.c
@@ -1530,7 +1530,7 @@
 	return change;
 }
 
-static struct snd_kcontrol_new snd_ens1373_rear =
+static const struct snd_kcontrol_new snd_ens1373_rear =
 {
 	.iface =	SNDRV_CTL_ELEM_IFACE_MIXER,
 	.name =		"AC97 2ch->4ch Copy Switch",
@@ -1575,7 +1575,7 @@
 	return changed;
 }
 
-static struct snd_kcontrol_new snd_ens1373_line =
+static const struct snd_kcontrol_new snd_ens1373_line =
 {
 	.iface =	SNDRV_CTL_ELEM_IFACE_MIXER,
 	.name =		"Line In->Rear Out Switch",