m68knommu: remove bogus definition of MBAR for ColdFire 532x family

Remove the bogus definition of the MBAR register for the ColdFire 532x
family. It doesn't have an MBAR register, its peripheral registers are
at fixed addresses and are not relative to a settable base.

All the code that relyed on this definition existing has been cleaned
up. The register address definitions now include the base as required.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>