arm: mvebu: don't hardcode the physical address for mvebu-mbus

Since the mvebu-mbus driver doesn't yet have a DT binding (and this DT
binding may not necessarily be ready for 3.11), the physical address
of the mvebu-mbus registers are currently hardcoded. This doesn't play
well with the fact that the internal registers base address may be
different depending on the bootloader.

In order to have only one central place for the physical address of
the internal registers, we now use of_translate_address() to translate
the mvebu-mbus register offsets into the real physical address, by
using DT-based address translation. This will go away once the
mvebu-mbus driver gains a proper DT binding.

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>