ASoC: constify gpio_chip structures

These structures are only used to copy into other structures, so declare
them as const.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct gpio_chip i@p = { ... };

@ok@
identifier r.i;
expression e;
position p;
@@
e = i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct gpio_chip e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct gpio_chip i = { ... };
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8903.c

@@ -1830,7 +1830,7 @@ static void wm8903_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 			   !!value << WM8903_GP1_LVL_SHIFT);
 }
 
-static struct gpio_chip wm8903_template_chip = {
+static const struct gpio_chip wm8903_template_chip = {
 	.label			= "wm8903",
 	.owner			= THIS_MODULE,
 	.request		= wm8903_gpio_request,