ARM: orion: convert the irq_reg_{readl,writel} calls to the new API

ARM: orion: convert the irq_reg_{readl,writel} calls to the new API

The commit "genirq: Generic chip: Change irq_reg_{readl,writel}
arguments" modified the API. In the same tome the
arch/arm/plat-orion/gpio.c file received a fix with the use of the old
API: "ARM: orion: Fix for certain sequence of request_irq can cause
irq storm". This commit fixes the use of the API.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Olof Johansson <olof@lixom.net>
Link: https://lkml.kernel.org/r/1416928752-24529-1-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>