KERNFS symbol is selected by SYSFS, so place it in generic config. Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> git-svn-id: svn://svn.openwrt.org/openwrt/trunk@44615 3c298f89-4303-0410-b956-a3cf2f4a3e73