MIPS: Octeon: add SNIC10E board

The CN6640-SNIC10E-G and CN6640-SNIC10E-1.1-G PCIe NICs are based on
this board.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>