MIPS: sead3: Do not overlap CPU/GIC IRQ ranges

In preparation for GIC IRQ domain support, assign a GIC IRQ base
that does not overlap with the CPU IRQs.

Note that this breaks SEAD-3 when the GIC is in EIC mode, though
I'm not convinced it was working before either.  It will be fixed
in the following patches.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Tested-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Jeffrey Deans <jeffrey.deans@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Jonas Gorski <jogo@openwrt.org>
Cc: John Crispin <blogic@openwrt.org>
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7813/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>