Q35: Windows BSOD running on 6.1.0
Description of problem:
Starting with QEMU 6.1.0, Windows no longer boots with Q35 (including `pc-q35-6.0` as well). When booting an existing Windows 7 installation, BSOD appears during boot (0x0000007B). If you try to install Windows from an ISO, the follow error appears when you try to start setup.

![Screen_Shot_2021-09-05_at_1.58.05_PM](/uploads/cfa04f25e9a8dc5ca8f201c87794b6c7/Screen_Shot_2021-09-05_at_1.58.05_PM.png)

Other people also reported similar issues booting Windows 10, as well as during use of Windows XP.
Steps to reproduce:
Enter commands from above.
Additional information:
This was not an issue in QEMU 6.0.0. I can reproduce it at `master`.