most: core: Constify static attribute_group structs

The only usage of these is to put their addresses in arrays of pointers
to const attribute_groups. Make them const to allow the compiler to put
them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20210108221512.18811-1-rikard.falkeborn@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>