Commit e4c6bfd2 ("mm: rearrange
vm_area_struct for fewer cache misses") changed the layout of the
vm_area_struct structure, it broke several SPARC32 assembly routines
which used numerical constants for accessing the vm_mm field.

This patch defines the VMA_VM_MM constant to replace the immediate values.
Signed-off-by: NOlivier DANET <odanet@caramail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>