PSA Direct-Mapped Registers

[jnfoster]

Is there a reason that PSA supports direct-mapped counters and meters but not registers? They seems like a very useful abstraction and were a part of P4_14, so I presume there exist targets that can implement them...

Not urgent, but creating this issue in case it was indeed just an oversight.

[jafingerhut]

I believe it is an oversight, and seems worth adding to me.