From: Patrick Mochel <mochel@digitalimplant.org>

Here is a patch to make sysfs optional.  Note that with CONFIG_SYSFS=n you
must specify the boot device's major:minor on the kernel boot command line
with

	root=03:01

For embedded systems, it will save a significant amount of memory during
runtime.  And, it saves 4k from the built kernel image for me.