These functions relied entirely on the presence of 'pkey->pmeth',
which is NULL on provider only keys. This adds an interface to get
domparam and key data from a provider, given corresponding provider
data (the actual domparam or key).
The retrieved data is cached in the EVP_PKEY structure (lending the
idea from provided EVP_CIPHER).
Reviewed-by: Nicola Tuveri <nic.tuv@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/10778)
6508e85883