crypto: hmac: move crypto/hmac.h into include/crypto/

Moves crypto/hmac.h into include/crypto/, likes cipher.h and hash.h

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>