Merge tag 'irqchip-4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core

Pull the second batch of irqchip updates for 4.15 from marc Zyngier:

 - A number of MIPS GIC updates and cleanups
 - One GICv4 update
 - Another firmware workaround for GICv2
 - Support for Mason8 GPIOs
 - Tiny documentation fix