mm/userfaultfd: disable userfaultfd-wp on x86_32

Userfaultfd-wp is not yet working on 32bit hosts, but it's accidentally
enabled previously.  Disable it.

Fixes: 5a28106 ("userfaultfd: wp: add WP pagetable tracking to x86")
Reported-by: Naresh Kamboju <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Peter Xu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Naresh Kamboju <[email protected]>
Reviewed-by: Andrea Arcangeli <[email protected]>
Cc: Hillf Danton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

Author: xzpeter

arch/x86/Kconfig

@@ -149,7 +149,7 @@ config X86
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64
-	select HAVE_ARCH_USERFAULTFD_WP		if USERFAULTFD
+	select HAVE_ARCH_USERFAULTFD_WP         if X86_64 && USERFAULTFD
 	select HAVE_ARCH_VMAP_STACK		if X86_64
 	select HAVE_ARCH_WITHIN_STACK_FRAMES
 	select HAVE_ASM_MODVERSIONS