bus: cdmm: Add MIPS R5 arch support

CDMM may be available not only on MIPS R2 architectures, but also on
newer MIPS R5 chips. For instance our P5600 chip has one. Let's mark
the CDMM bus being supported for that MIPS arch too.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>