Merge tag 'irqchip-3.16' of git://git.infradead.org/users/jcooper/linux into irq/core

irqchip core changes for v3.16 collected by Jason Cooper:
 - irq-gic: Use a mask field
 - irq-armada-370-xp: Move the DT binding docs to the irqchip directory
 - irq-brcmstb-l2: New driver for Broadcom Set Top Box Level-2