Some AMD CPUs (e.g. AMD A4-6250J and AMD Ryzen 3000-series) have a
failing random generation instruction, which always returns
0xffffffff, even when generation was "successful".
This code checks if hardware random generator generates four consecutive
equal numbers. If it does, then we probably have a failing one and
should disable it completely.
Change-Id: I38c87920ca2e8cce4143afbff5e453ce3845d11a
Fixes: QTBUG-69423
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>