x86: remove unnecessary #ifdef CONFIG_X86_32...#else

Remove the #ifdef conditional because this comparison is already done in
user_mode_vm().

Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Cc: akpm@osdl.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>