raspberrypi3-64 and raspberrypi4-64 fail to initialize hwrng

[rcooke-warwick]

for the above device types, rngd fails to initialise the hwrng entropy source:

Aug 06 14:41:01 rngd[1518]: Initializing available sources
Aug 06 14:41:01 rngd[1518]: [hwrng ]: Initialized
Aug 06 14:41:01 rngd[1518]: [rndr  ]: No HW SUPPORT
Aug 06 14:41:01 rngd[1518]: [rndr  ]: Initialization Failed

This problem doesn't appear on the raspberrypi3 or fincm3 device types

[jellyfish-bot]

[rcooke-warwick] This has attached https://jel.ly.fish/a13bcce9-7878-465c-940f-cd12b1d27a37

[rcooke-warwick]

I wouldn't be opposed to adding a simple test to the OS test suite too, to just check the logs to see if hwrng initialised without issue

[rcooke-warwick]

Ok I looked at this again and I realised I made a mistake - hwrng does initialise fine, its rndr that doesn't - which is:

    Entropy drawn from the RNDR instruction (aarch64 only)

So I'm not sure if this is actually a problem