KVM: arm64: vgic-v3: Enable trapping of Group-1 system registers

KVM: arm64: vgic-v3: Enable trapping of Group-1 system registers

BugLink: https://bugs.launchpad.net/bugs/1673564
In order to be able to trap Group-1 GICv3 system registers, we need to
set ICH_HCR_EL2.TALL1 before entering the guest. This is conditionally
done after having restored the guest's state, and cleared on exit.

Tested-by: Alexander Graf <agraf@suse.de>
Acked-by: David Daney <david.daney@cavium.com>
Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
(backported from commit 9c7bfc288c71068ab323b802dba2eb87fd08b127)
[ dannf: Context adjustments ]
Signed-off-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>