irqchip: arm-gic: Define additional MMIO offsets and masks

Define CPU interface offsets for the GICC_ABPR, GICC_APR, and GICC_IIDR
registers.  Define distributor registers for the GICD_SPENDSGIR and the
GICD_CPENDSGIR.  KVM/ARM needs to know about these definitions to fully
support save/restore of the VGIC.

Also define some masks and shifts for the various GICH_VMCR fields.

Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>