MIPS: Octeon: Make CSR functions node aware.

Updates CSR read/write functions to be aware of nodes present in
systems with CIU3 support.

Signed-off-by: Steven J. Hill <Steven.Hill@cavium.com>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-watchdog@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17211/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>