nfsd4: support BIND_CONN_TO_SESSION

Basic xdr and processing for BIND_CONN_TO_SESSION.  This adds a
connection to the list of connections associated with a session.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index cf6dc83..442f6d8 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -148,6 +148,11 @@
 	u32				gid;
 };
 
+struct nfsd4_bind_conn_to_session {
+	struct nfs4_sessionid		sessionid;
+	u32				dir;
+};
+
 /* The single slot clientid cache structure */
 struct nfsd4_clid_slot {
 	u32				sl_seqid;