Use PSA drivers to manage built-in crypto acceleration

[gilles-peskine-arm]

The PSA accelerator driver mechanism, as specified, can handle the accelerated crypto modules that we ship (AESNI, AESCE, SHA256 and SHA512 acceleration on armv8-A). This is only practical once the tooling is fully mature, so that users can easily choose between having optional acceleration with fallback, acceleration only or no acceleration.

If the tooling isn't mature enough by the time of the 4.0 release, or if we don't want to put in the work before 4.0, we could potentially do this in a 4.x minor release, keeping the existing options for compatibility but using the driver structure under the hood. This would break for people who have their own handwritten driver wrapper file, which may or may not be a concern.

Related: Mbed-TLS/TF-PSA-Crypto#99