ARM: KVM: fix L2CTLR to be per-cluster

ARM: KVM: fix L2CTLR to be per-cluster

commit 9cbb6d969cb6561de45d917b8bb9281cb374bb35 upstream.

The L2CTLR register contains the number of CPUs in this cluster.

Make sure the register content is actually relevant to the vcpu
that is being configured by computing the number of cores that are
part of its cluster.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>