leds: blinkm: constify attribute_group structures.

attribute_group are not supposed to change at runtime. All functions
working with attribute_group provided by <linux/sysfs.h> work with
const attribute_group. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <[e-mail]>
Signed-off-by: Jacek Anaszewski <[e-mail]>

drivers/leds/leds-blinkm.c

···
 	NULL,
 };
 
-static struct attribute_group blinkm_group = {
+static const struct attribute_group blinkm_group = {
 	.name = "blinkm",
 	.attrs = blinkm_attrs,
 };