MIPS: OCTEON: Consolidate the edge and level irq_chip structures.

We can consolidate octeon_irq_chip_ciu_edge and octeon_irq_chip_ciu as
they only differ in the .irq_ack element, and that is unused by the
level handler.  This gets rid of a bunch of duplicate definitions.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc:  linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3931/


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