Octeon: Fix interrupt irq settings for performance counters.

Octeon uses different interrupt irq for timer and performance counters.
Set CvmCtl[IPPCI] to correct irq value very early.

Signed-off-by: Chandrakala Chavva <cchavva@caviumnetworks.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Patchwork: https://patchwork.linux-mips.org/patch/2085/


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