irqchip/faraday: Replace moxa with ftintc010

The Moxa Art interrupt controller is very very likely just an instance
of the Faraday FTINTC010 interrupt controller from Faraday Technology.
An indication would be its close association with the FA526 ARM core
and the fact that the register layout is the same.

The implementation in irq-moxart.c can probably be right off replaced
with the irq-ftintc010.c driver by adding a compatible string, selecting
this irqchip from the machine and run.

As a bonus we have an irqchip driver supporting high/low and
rising/falling edges for the Moxa Art, and shared code with the Gemini
platform.

Acked-by: Olof Johansson <olof@lixom.net>
Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>