CIFS: add sha512 secmech

* prepare for SMB3.11 pre-auth integrity
* enable sha512 when SMB311 is enabled in Kconfig
* add sha512 as a soft dependency

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

fs/cifs/cifsencrypt.c

@@ -829,6 +829,11 @@ cifs_crypto_secmech_release(struct TCP_Server_Info *server)
 		server->secmech.md5 = NULL;
 	}
 
+	if (server->secmech.md5) {
+		crypto_free_shash(server->secmech.sha512);
+		server->secmech.sha512 = NULL;
+	}
+
 	if (server->secmech.hmacmd5) {
 		crypto_free_shash(server->secmech.hmacmd5);
 		server->secmech.hmacmd5 = NULL;
@@ -852,4 +857,6 @@ cifs_crypto_secmech_release(struct TCP_Server_Info *server)
 	server->secmech.sdeschmacmd5 = NULL;
 	kfree(server->secmech.sdescmd5);
 	server->secmech.sdescmd5 = NULL;
+	kfree(server->secmech.sdescsha512);
+	server->secmech.sdescsha512 = NULL;
 }