dt-bindings: gpio: uniphier: add UniPhier GPIO binding

This GPIO controller is used on UniPhier SoC family.

The vendor specific property "socionext,interrupt-ranges" is for
specifying interrupt mapping to the parent interrupt controller
because the mapping is not contiguous.  It works like "ranges",
but transforms "interrupts" instead of "reg".

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 00c8be7..193b861 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2017,6 +2017,7 @@
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-uniphier.git
 S:	Maintained
+F:	Documentation/devicetree/bindings/gpio/gpio-uniphier.txt
 F:	arch/arm/boot/dts/uniphier*
 F:	arch/arm/include/asm/hardware/cache-uniphier.h
 F:	arch/arm/mach-uniphier/