iio: light: zopt2201: make zopt2201_scale const

Add const qualifier to struct zopt2201_scale zopt2201_scale_*[]. This
is read-only data so it can be made const.

Signed-off-by: David Lechner <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/light/zopt2201.c

···
 	u8 res; /* resolution register value */
 };
 
-static struct zopt2201_scale zopt2201_scale_als[] = {
+static const struct zopt2201_scale zopt2201_scale_als[] = {
 	{ 19, 200000, 0, 5 },
 	{  6, 400000, 1, 5 },
 	{  3, 200000, 2, 5 },
···
 	{  0,   8333, 4, 0 },
 };
 
-static struct zopt2201_scale zopt2201_scale_uvb[] = {
+static const struct zopt2201_scale zopt2201_scale_uvb[] = {
 	{ 0, 460800, 0, 5 },
 	{ 0, 153600, 1, 5 },
 	{ 0,  76800, 2, 5 },
···
 }
 
 static int zopt2201_write_scale_by_idx(struct zopt2201_data *data, int idx,
-				     struct zopt2201_scale *zopt2201_scale_array)
+				       const struct zopt2201_scale *zopt2201_scale_array)
 {
 	int ret;