Define AESNI_ASM if AESNI assembler is included, and use it

Define AESNI_ASM if AESNI assembler is included, and use it

Because we have cases where basic assembler support isn't present, but
AESNI asssembler support is, we need a separate macro that indicates
that, and use it.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/10080)