m68k: allow ColdFire 547x and 548x CPUs to be built with MMU enabled

The ColdFire 547x and 548x CPUs have internal MMU hardware. All code
to support this is now in, so we can build kernels with it enabled.

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>