minimal build fixes for uml (fallout from x86 merge)

a) include/asm-um/arch can't just point to include/asm-$(SUBARCH) now
 b) arch/{i386,x86_64}/crypto are merged now
 c) subarch-obj needed changes
 d) cpufeature_64.h should pull "cpufeature_32.h", not <asm/cpufeature_32.h>
    since it can be included from asm-um/cpufeature.h
 e) in case of uml-i386 we need CONFIG_X86_32 for make and gcc, but not
    for Kconfig
 f) sysctl.c shouldn't do vdso_enabled for uml-i386 (actually, that one
    should be registered from corresponding arch/*/kernel/*, with ifdef
    going away; that's a separate patch, though).

With that and with Stephen's patch ("[PATCH net-2.6] uml: hard_header fix")
we have uml allmodconfig building both on i386 and amd64.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/sys-i386/Makefile

@@ -4,9 +4,9 @@ obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
 
 obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
 
-subarch-obj-y = lib/bitops.o lib/semaphore.o lib/string.o
-subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem.o
-subarch-obj-$(CONFIG_MODULES) += kernel/module.o
+subarch-obj-y = lib/bitops_32.o lib/semaphore_32.o lib/string_32.o
+subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem_32.o
+subarch-obj-$(CONFIG_MODULES) += kernel/module_32.o
 
 USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o