KVM: arm64: add active register handling to GICv3 emulation as well

Commit 47a98b15

 ("arm/arm64: KVM: support for un-queuing active
IRQs") introduced handling of the GICD_I[SC]ACTIVER registers,
but only for the GICv2 emulation. For the sake of completeness and
as this is a pre-requisite for save/restore of the GICv3 distributor
state, we should also emulate their handling in the distributor and
redistributor frames of an emulated GICv3.

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>