arm: mach-orion5x: convert to use mvebu-mbus driver

This commit migrates the mach-orion5x platforms to use the mvebu-mbus
driver and therefore removes the Orion5x-specific addr-map code.

The dove_init_early() function now initializes the mvebu-mbus driver
by calling mvebu_mbus_init().

We also convert a number of orion5x_setup_xyz_win() calls to the
appropriate mvebu_mbus_add_window() calls, as each board was doing its
own setup for the NOR window or other devices. Ultimately, those
devices will be probed from the DT.

The common address decoding windows are now registered in the
orion5x_setup_wins() function. It is worth noting that the four PCIe
address decoding windows will ultimately no longer have to be
registered here: it will be done automatically by the PCIe driver once
Dove has been migrated to use the upcoming mvebu PCIe driver.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>