m68k: add TLB flush support for the ColdFire V4e MMU hardware

The ColdFire V4e MMU is unlike any of the other m68k MMU hardware.
It needs its own TLB flush support code.

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>