ARM: Orion: mbus_dram_info consolidation

Move the *_mbus_dram_info structure into the orion platform and call it
orion_mbus_dram_info everywhere.

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>