KVM: arm/arm64: vgic: Reset base address on kvm_vgic_dist_destroy()

On vgic_dist_destroy(), the addresses are not reset. However for
kvm selftest purpose this would allow to continue the test execution
even after a failure when running KVM_RUN. So let's reset the
base addresses.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210405163941.510258-5-eric.auger@redhat.com