[RAPIDIO] Add RapidIO node into MPC8641HPCN dts file

This adds properties describing the RapidIO controller to the
device-tree source for the MPC8641HPCN board.

Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>