livepatch: fix format string in kobject_init_and_add()

kobject_init_and_add() takes expects format string for a name, so we
better provide it in order to avoid infoleaks if modules craft their
mod->name in a special way.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Reported-by: Kees Cook <keescook@chromium.org>
Acked-by: Seth Jennings <sjenning@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>