CA-265413:  Disable passthrough when using MxGPU
CA-265413:  Disable passthrough when using MxGPU

MxGPU and passthrough cannot be used on the same host.
Workaround is that AMD will define an MxGPU.1 device which is
equivalent to passthrough of the whole PF, using the MxGPU
architecture.

srowe/xen-api,srowe/xen-api,srowe/xen-api,srowe/xen-api,srowe/xen-api