irqchip/sunxi-nmi: Switch to of_io_request_and_map() from of_iomap()

Switch to the new of_io_request_and_map() call, so the IO resource is
properly held, and also shows up in /proc/iomem.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: http://lkml.kernel.org/r/1444063334-19832-3-git-send-email-wens@csie.org


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>