MIPS: Oceton: Update model detection code for new chips.

Several newer chips were not covered, update the code to detect them.
This necessitates updating cvmx-mio-defs.h as well, because it has new
and required definitions.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2939/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>