xen-platform: add support for unplugging NVMe disks...

...not just IDE and SCSI.

This patch allows the Xen tool-stack to fully support of NVMe as an
emulated disk type. See [1] for the relevant tool-stack patch discussion.

[1] https://lists.xen.org/archives/html/xen-devel/2017-01/msg01225.html

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

hw/i386/xen/xen_platform.c

@@ -120,6 +120,7 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *o)
         break;
 
     case PCI_CLASS_STORAGE_SCSI:
+    case PCI_CLASS_STORAGE_EXPRESS:
         object_unparent(OBJECT(d));
         break;