MIPS: Octeon: Rewrite interrupt handling code.

This includes conversion to new style irq_chip functions, and
correctly enabling/disabling per-CPU interrupts.

The hardware interrupt bit to irq number mapping is now done with a
flexible map, instead of by bit twiddling the irq number.

[ tglx: Adjusted to new irq_cpu_on/offline callbacks and
        __irq_set_affinity_lock ]

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: ralf@linux-mips.org
LKML-Reference: <1301081931-11240-5-git-send-email-ddaney@caviumnetworks.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>