SUNRPC: Add an rpc_credop callback for binding a credential to an rpc_task

We need the ability to treat 'generic' creds specially, since they want to
bind instances of the auth cred instead of binding themselves.

Signed-off-by: Trond Myklebust <[email protected]>
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index ef63849..d34f6df 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1300,6 +1300,7 @@
 	.cr_name	= "AUTH_GSS",
 	.crdestroy	= gss_destroy_cred,
 	.cr_init	= gss_cred_init,
+	.crbind		= rpcauth_generic_bind_cred,
 	.crmatch	= gss_match,
 	.crmarshal	= gss_marshal,
 	.crrefresh	= gss_refresh,
@@ -1311,6 +1312,7 @@
 static const struct rpc_credops gss_nullops = {
 	.cr_name	= "AUTH_GSS",
 	.crdestroy	= gss_destroy_cred,
+	.crbind		= rpcauth_generic_bind_cred,
 	.crmatch	= gss_match,
 	.crmarshal	= gss_marshal,
 	.crrefresh	= gss_refresh_null,