mm: introduce arch-specific vma flag VM_ARCH_1

Combine several arch-specific vma flags into one.

before patch:

        0x00000200      0x01000000      0x20000000      0x40000000
x86     VM_NOHUGEPAGE   VM_HUGEPAGE     -               VM_PAT
powerpc -               -               VM_SAO          -
parisc  VM_GROWSUP      -               -               -
ia64    VM_GROWSUP      -               -               -
nommu   -               VM_MAPPED_COPY  -               -
others  -               -               -               -

after patch:

        0x00000200      0x01000000      0x20000000      0x40000000
x86     -               VM_PAT          VM_HUGEPAGE     VM_NOHUGEPAGE
powerpc -               VM_SAO          -               -
parisc  -               VM_GROWSUP      -               -
ia64    -               VM_GROWSUP      -               -
nommu   -               VM_MAPPED_COPY  -               -
others  -               VM_ARCH_1       -               -

And voila! One completely free bit.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>