arm64: its: Handle its command queue wrapping

Because micro-bench may send a large number of ITS commands, we
should handle ITS command queue wrapping as kernel instead of just
failing the test.

Signed-off-by: Jingyi Wang <wangjingyi11@huawei.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>