KVM: ARM: vgic: Fix the overlap check action about setting the GICD & GICC base address.

Currently below check in vgic_ioaddr_overlap will always succeed,
because the vgic dist base and vgic cpu base are still kept UNDEF
after initialization. The code as follows will be return forever.

	if (IS_VGIC_ADDR_UNDEF(dist) || IS_VGIC_ADDR_UNDEF(cpu))
                return 0;

So, before invoking the vgic_ioaddr_overlap, it needs to set the
corresponding base address firstly.

Signed-off-by: Haibin Wang <wanghaibin.wang@huawei.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>