ARM: Orion: Get address map from plat-orion instead of via platform_data

Use an getter function in plat-orion/addr-map.c to get the address map
structure, rather than pass it to drivers in the platform_data
structures. When the drivers are built for none orion platforms, a
dummy function is provided instead which returns NULL.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Michael Walle <michael@walle.cc>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>