attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.
File size before:
text data bss dec hex filename
621 176 0 797 31d drivers/devfreq/governor_userspace.o
File size After adding 'const':
text data bss dec hex filename
670 144 0 814 32e drivers/devfreq/governor_userspace.o