Support for a CROSSBAR ip that precedes the main interrupt controller.
The primary irqchip invokes the crossbar's callback which inturn allocates
a free irq and configures the IP. Thus the peripheral interrupts are
routed to one of the free irqchip interrupt lines.
The primary irqchip invokes the crossbar's callback which inturn allocates
a free irq and configures the IP. Thus the peripheral interrupts are
routed to one of the free irqchip interrupt lines.