x86_32, mm: Remove user bit from identity map PDE

The only reason that the user bit was set was to support userspace
access to the compat vDSO in the fixmap.  The compat vDSO is gone,
so the user bit can be removed.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/e240a977f3c7cbd525a091fd6521499ec4b8e94f.1394751608.git.luto@amacapital.net


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>