Windows XP takes much longer to boot in TCG mode since 5.0

This bug has been copied automatically from: https://bugs.launchpad.net/qemu/+bug/1883593
Reported by 'Randy Rhoads' on 2020-06-15 :

Since upgrading from 4.2 to 5.0, a Windows XP VM takes much longer to
boot.

It hangs about three minutes on "welcome" screen with the blue background,
while previously the total boot time was less than a minute.

The issue only happens in TCG mode (not with KVM) and also happens with
the current master which includes the uring patches (7d3660e7).

I can reproduce this issue with a clean XP install with no flags other
than `-m 2G`. After booting, the performance seems to be normal.