SUNRPC: Add a generic RPC credential

Add an rpc credential that is not tied to any particular auth mechanism,
but that can be cached by NFS, and later used to look up a cred for
whichever auth mechanism that turns out to be valid when the RPC call is
being made.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/auth.h b/include/linux/sunrpc/auth.h
index 348546c..70644ed 100644
--- a/include/linux/sunrpc/auth.h
+++ b/include/linux/sunrpc/auth.h
@@ -125,9 +125,12 @@
 extern const struct rpc_authops	authnull_ops;
 
 void __init		rpc_init_authunix(void);
+void __init		rpc_init_generic_auth(void);
 void __init		rpcauth_init_module(void);
 void __exit		rpcauth_remove_module(void);
+void __exit		rpc_destroy_generic_auth(void);
 
+struct rpc_cred *	rpc_lookup_cred(void);
 int			rpcauth_register(const struct rpc_authops *);
 int			rpcauth_unregister(const struct rpc_authops *);
 struct rpc_auth *	rpcauth_create(rpc_authflavor_t, struct rpc_clnt *);