genirq: Implement a generic interrupt chip

[Tony Lindgren]

* Thomas Gleixner <tglx at linutronix.de> [110416 14:20]:
> --- linux-2.6.orig/include/linux/irq.h
> +++ linux-2.6/include/linux/irq.h
...

> +/**
> + * struct irq_chip_regs - register offsets for struct irq_gci
> + * @enable:	Enable register offset to reg_base
> + * @disable:	Disable register offset to reg_base
> + * @mask:	Mask register offset to reg_base
> + * @ack:	Ack register offset to reg_base
> + * @ack:	Secondary Ack register offset to reg_base

Two @ack lines here?

Tony