[PATCH] uml: inclusion cleanup

The completion cleanup got rid of some semaphores, but didn't remove the
inclusion of asm/semaphore.h from xterm_kern.c.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>