ppc32: Radstone PPC7D platform update

- Recent mv643xx #define name changes broke the PPC7D platform
compile. Fixed by this patch.

- Change default platform config to add mv643xx_eth and mv64xxx-i2c
config options.

- Add i2c platform data and update to cope with recent platform device
name change.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Mark A. Greer <mgreer@mvista.com>
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