[PATCH] UML: Fix a compile warning

An eliminated warning from Chris Wright.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/kernel/skas/process.c

@@ -92,6 +92,7 @@ static int userspace_tramp(void *arg)
 }
 
 /* Each element set once, and only accessed by a single processor anyway */
+#undef NR_CPUS
 #define NR_CPUS 1
 int userspace_pid[NR_CPUS];