[PATCH] uml: fix missing subdir in x86_64

make distclean et.al.  are missing arch/um/sys-x86_64/utils; fixed the same
way we have it done for sys-i386 counterpart.
Signed-off-by: NAl Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/um/sys-x86_64/Makefile

@@ -29,3 +29,5 @@ thunk.S-dir = lib
 module.c-dir = kernel
 
 CFLAGS_csum-partial.o := -Dcsum_partial=arch_csum_partial
+
+subdir- := util