Fix some odd names in our provider source code

Fix some odd names in our provider source code

ecossl_dh_keyexch_functions     -> ossl_ecdh_keyexch_functions
ecossl_dsa_signature_functions  -> ossl_ecdsa_signature_functions
sm2_asym_cipher_functions       -> ossl_sm2_asym_cipher_functions
sm2_keymgmt_functions           -> ossl_sm2_keymgmt_functions
sm2_signature_functions         -> ossl_sm2_signature_functions

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14028)