[ARM] Orion: I2C support

The Orion I2C controller is the same one used in the Discovery
family (MV643XX). This patch include the common platform_device
stuff according to the existing i2c_mv64xxx.c conventions.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Signed-off-by: Tzachi Perelstein <tzachi@marvell.com>