pwm: constify pwm_ops structures

Declare pwm_ops structures as const as they are only stored in the ops
field of a pwm_chip structure. This field is of type const struct pwm_ops
*, so pwm_ops structures having this property can be declared as const.
Done using Coccinelle:

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

@ok1@
identifier r1.i;
position p;
struct pxa_pwm_chip pwm;
struct bfin_pwm_chip bwm;
struct vt8500_chip vp;
struct imx_chip icp;
@@
(
pwm.chip.ops=&i@p
|
bwm.chip.ops=&i@p
|
vp.chip.ops=&i@p
|
icp.chip.ops=&i@p
)

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

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

File size details:

   text	   data	    bss	    dec	    hex	filename
   1646	    328	      0	   1974	    7b6	drivers/pwm/pwm-imx.o
   1742	    224	      0	   1966	    7ae	drivers/pwm/pwm-imx.o

   1941	    296	      0	   2237	    8bd	drivers/pwm/pwm-pxa.o
   2037	    192	      0	   2229	    8b5	drivers/pwm/pwm-pxa.o

   1946	    296	      0	   2242	    8c2	drivers/pwm/pwm-vt8500.o
   2050	    192	      0	   2242	    8c2	drivers/pwm/pwm-vt8500.o

The drivers/pwm/pwm-bfin.o file did not compile.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-bfin.c

@@ -103,7 +103,7 @@ static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	disable_gptimer(priv->pin);
 }
 
-static struct pwm_ops bfin_pwm_ops = {
+static const struct pwm_ops bfin_pwm_ops = {
 	.request = bfin_pwm_request,
 	.free = bfin_pwm_free,
 	.config = bfin_pwm_config,

drivers/pwm/pwm-imx.c

@@ -240,7 +240,7 @@ static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	clk_disable_unprepare(imx->clk_per);
 }
 
-static struct pwm_ops imx_pwm_ops = {
+static const struct pwm_ops imx_pwm_ops = {
 	.enable = imx_pwm_enable,
 	.disable = imx_pwm_disable,
 	.config = imx_pwm_config,

drivers/pwm/pwm-pxa.c

@@ -118,7 +118,7 @@ static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	clk_disable_unprepare(pc->clk);
 }
 
-static struct pwm_ops pxa_pwm_ops = {
+static const struct pwm_ops pxa_pwm_ops = {
 	.config = pxa_pwm_config,
 	.enable = pxa_pwm_enable,
 	.disable = pxa_pwm_disable,

drivers/pwm/pwm-vt8500.c

@@ -184,7 +184,7 @@ static int vt8500_pwm_set_polarity(struct pwm_chip *chip,
 	return 0;
 }
 
-static struct pwm_ops vt8500_pwm_ops = {
+static const struct pwm_ops vt8500_pwm_ops = {
 	.enable = vt8500_pwm_enable,
 	.disable = vt8500_pwm_disable,
 	.config = vt8500_pwm_config,