[PATCH] docs: small kbuild cleanup

While reading this I noticed that the contents of this document list
section "3.8 Command line dependency" but it doesn't exist in the document.

Signed-off-by: Daniel Walker <dwalker@mvista.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>