irqchip/sunxi-nmi: Support sun9i A80 NMI controller

The A80 moves the NMI controller into the PRCM address space, and also
rearranges the registers.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lkml.kernel.org/r/1449130813-22400-4-git-send-email-wens@csie.org
Signed-off-by: Jason Cooper <jason@lakedaemon.net>