irqchip: brcmstb-l2: Add Broadcom Set Top Box Level-2 interrupt controller

irqchip: brcmstb-l2: Add Broadcom Set Top Box Level-2 interrupt controller

This patch adds support for the Level-2 interrupt controller hardware
found in Broadcom Set Top Box System-on-a-Chip devices. This interrupt
controller is implemented using the generic IRQ chip driver with
separate enable and disable registers.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Link: https://lkml.kernel.org/r/1400892054-24457-2-git-send-email-f.fainelli@gmail.com
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>