[PATCH] block: Constify attribute_group structures.

attribute_groups are not supposed to change at runtime. All functions working with attribute_groups provided by work with const attribute_group. So mark the non-const structs as const. File size before: textdata bss dec hex filename 5302 544 0584616d6 block

[PATCH] block: constify attribute_group structures.

attribute_groups are not supposed to change at runtime. All functions working with attribute_groups provided by work with const attribute_group. So mark the non-const structs as const. File size before: textdata bss dec hex filename 11622 9122076 146103912 block