Generalize mbedtls_pk_setup_opaque to MBEDTLS_PSA_CRYPTO...
Extendmbedtls_pk_setup_opaqueto provide support forMBEDTLS_PK_OPAQUEwhenever PSA crypto API functions are available, i.e. wheneverMBEDTLS_PSA_CRYPTO_CLIENTis enabled, regardless of the status ofMBEDTLS_USE_PSA_