Work around German Windows ISO NIC detection fallout

Use global qemu hotplug switches to handle the Qemu issue #774
reported in

https://gitlab.com/qemu-project/qemu/-/issues/774

whereby we cannot detect the NICs on any Windows 10 and later version
after an unattended install.

tp_folder/configs/guest-os.cfg

@@ -648,6 +648,9 @@ variants:
                 os_variant = win10
                 image_name = win10
                 nic_wname = "Ethernet"
+                # TODO: hotplug disabling globals needed for German ISO Windows
+                # as described in: https://gitlab.com/qemu-project/qemu/-/issues/774
+                extra_params = " -global PIIX4_PM.acpi-root-pci-hotplug=off -global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off"
                 variants:
                     - x86_64:
                         image_name += -64