m68k: page table support definitions and code for ColdFire MMU

The ColdFire V4e MMU is nothing like any of the other m68k MMU's.
So we need to create a set of definitions and support routines
for the kernels paging functions.

This is largely taken from Freescales BSP code for this (though it
was a 2.6.25 kernel). I have cleaned it up alot from the original.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Matt Waddel <mwaddel@yahoo.com>
Acked-by: Kurt Mahan <kmahan@xmission.com>