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>
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 05287b0..3b8e9c2 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -202,4 +202,7 @@ extern int smb3_validate_negotiate(const unsigned int, struct cifs_tcon *);
 
 extern enum securityEnum smb2_select_sectype(struct TCP_Server_Info *,
 					enum securityEnum);
+#ifdef CONFIG_CIFS_SMB311
+extern int smb311_crypto_shash_allocate(struct TCP_Server_Info *server);
+#endif
 #endif			/* _SMB2PROTO_H */