Add support for Nucleo l4r5

[cothan]

Fixes #54

• Does this PR change the input/output behaviour of a cryptographic algorithm (i.e., does it change known answer test values)? (If so, a version bump will be required from x.y.z to x.(y+1).0.)

[mkannwischer]

Thanks for adding this @cothan.
Works fine and looking mostly good.
Can you make the following changes/answer my questions please?

[mkannwischer]

If I am running
tests stack nucleo-l4r5zi -v

I'm getting the following

DEBUG > Waiting for start marker
DEBUG > Reading input
DEBUG > keypair stack usage:
4294967268
encaps stack usage:
4294967268
decaps stack usage:
4294967268
OK KEYS

That looks wrong. Do you also see that? Can you look into that, please? Stack measurements are always a bit fragile, unfortunately.

[cothan]

@mkannwischer , I confirm I see the same problem. I'm not sure why, all the code I copy from pqm4 repo. I'll look into it.