MIPS: Octeon: Add definitions for setting up SSO

Some Octeon II models have SSO instead of POW and use a different register
for setting the interrupt thresholds. Add the necessary definitions for
configuring the interrupts also on those models.

Signed-off-by: Janne Huttunen <janne.huttunen@nokia.com>
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: David Daney <david.daney@cavium.com>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Janne Huttunen <janne.huttunen@nokia.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: devel@driverdev.osuosl.org
Patchwork: https://patchwork.linux-mips.org/patch/10972/


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