struct irq_chip_regs — register offsets for struct irq_gci
struct irq_chip_regs {
  unsigned long enable;
  unsigned long disable;
  unsigned long mask;
  unsigned long ack;
  unsigned long eoi;
  unsigned long type;
  unsigned long polarity;
};  Enable register offset to reg_base
Disable register offset to reg_base
Mask register offset to reg_base
Ack register offset to reg_base
Eoi register offset to reg_base
Type configuration register offset to reg_base
Polarity configuration register offset to reg_base