wireless: iwlegacy: 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: David S. Miller <[e-mail]>

drivers/net/wireless/intel/iwlegacy/3945-mac.c

···
 	NULL
 };
 
-static struct attribute_group il3945_attribute_group = {
+static const struct attribute_group il3945_attribute_group = {
 	.name = NULL,		/* put in device directory */
 	.attrs = il3945_sysfs_entries,
 };