There are no longer any platforms that use Marvell's mv64x60
hostbridges so remove the supporting kernel code.

CC: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: NMark Greer <mgreer@animalcreek.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>