As already done for kvm_cpu_synchronize_state(), let's trigger
kvm_arch_put_registers() via run_on_cpu() for kvm_cpu_synchronize_post_reset()
and kvm_cpu_synchronize_post_init().

This way, we make sure that the register synchronizing ioctls are
called from the proper vcpu thread; this avoids calls to
synchronize_rcu() in the kernel.

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>