Win(PE) NIC issue with pc-q35-6.1
Description of problem:
When booting WinPE (via PXE via WDS) on a `pc-q35-6.1` machine, the NIC will not initialize.

What I got with `pnputil.exe /enum-devices /class net` is `Device has problem: 56 0x38 (CM_PROB_NEED_CLASS_CONFIG)` See: [CM_PROB_NEED_CLASS_CONFIG](https://docs.microsoft.com/en-us/windows-hardware/drivers/install/cm-prob-need-class-config)

I'm using virt manager and I've tried both `e1000e` and `virtio` network adapters (virtio with drivers injected into the image of course). Both yield the aforementioned error and `ipconfig` remains empty. This is an obscure problem - I haven't checked if a normal windows install behaves the same way, but it might be unique to winpe.

However, with `pc-q35-5.2`, the NIC initializes without a problem.
Steps to reproduce:
1. Create `pc-q35-6.1` based vm in virt manager with default settings (network bridged to network bridge)
2. PXE boot Windows Setup
3. Observe hang (observe errors with console `SHIFT+F10`)
Additional information: