iio: adc: constify iio_info structures

Declare iio_info structures as const as they are only stored in
the info field of a iio_dev structure. This field is of type const,
so iio_info structures having similar properties can be made const too.

File size before:
   text	   data	    bss	    dec	    hex	filename
   6944	    792	      0	   7736	   1e38	drivers/iio/adc/ti-ads1015.o

File size after:
   text   data	    bss	    dec	    hex	filename
   7264	    472	      0	   7736	   1e38	drivers/iio/adc/ti-ads1015.o

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/ti-ads1015.c

@@ -472,14 +472,14 @@ static const struct attribute_group ads1115_attribute_group = {
 	.attrs = ads1115_attributes,
 };
 
-static struct iio_info ads1015_info = {
+static const struct iio_info ads1015_info = {
 	.driver_module	= THIS_MODULE,
 	.read_raw	= ads1015_read_raw,
 	.write_raw	= ads1015_write_raw,
 	.attrs          = &ads1015_attribute_group,
 };
 
-static struct iio_info ads1115_info = {
+static const struct iio_info ads1115_info = {
 	.driver_module	= THIS_MODULE,
 	.read_raw	= ads1015_read_raw,
 	.write_raw	= ads1015_write_raw,