UPSTREAM: arm/arm64: KVM: Reset the HCR on each vcpu when resetting the vcpu

When userspace resets the vcpu using KVM_ARM_VCPU_INIT, we should also
reset the HCR, because we now modify the HCR dynamically to
enable/disable trapping of guest accesses to the VM registers.

This is crucial for reboot of VMs working since otherwise we will not be
doing the necessary cache maintenance operations when faulting in pages
with the guest MMU off.

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

Bug: 31432001
Change-Id: I787de8bfb304e20345307c890a5eb00b520b7af5
(cherry picked from commit b856a59141b1066d3c896a0d0231f84dabd040af)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>