Put all the MSI code in one place (msi-octeon.c).  This simplifies
octeon-irq.c and gets rid of some ugly #ifdefs
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1484/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>