openssl-util: pass the UI callback for interactive PIN prompts

openssl-util: pass the UI callback for interactive PIN prompts

Observed with the tpm2 provider and the tpm2tss engine was that the
auth process failed because the provider/engine could not ask for the
PIN through the callback, resulting in:
  "Failed to load private key from ...: Input/output error"
Apparently the default UI method is not enough and the key setup
functions expect an explicit method.
Pass the existing UI method through as callback for the key setup.