nfsd4: move client * to nfs4_stateid, add init_stid helper

This will be convenient.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index da68bf6..70062b7 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -81,6 +81,7 @@
 	unsigned char sc_type;
 	struct list_head sc_hash;
 	stateid_t sc_stateid;
+	struct nfs4_client *sc_client;
 };
 
 struct nfs4_delegation {
@@ -88,7 +89,6 @@
 	struct list_head	dl_perclnt;
 	struct list_head	dl_recall_lru;  /* delegation recalled */
 	atomic_t		dl_count;       /* ref count */
-	struct nfs4_client	*dl_client;
 	struct nfs4_file	*dl_file;
 	u32			dl_type;
 	time_t			dl_time;