NFS: Combine nfs_idmap_{init|quit}() and nfs_idmap_{init|quit}_keyring()

The idmap_init() and idmap_quit() functions only exist to call the
_keyring() version.  Let's just call the keyring() functions directly.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4idmap.c

@@ -184,7 +184,7 @@ static struct key_type key_type_id_resolver = {
 	.read		= user_read,
 };
 
-static int nfs_idmap_init_keyring(void)
+int nfs_idmap_init(void)
 {
 	struct cred *cred;
 	struct key *keyring;
@@ -230,7 +230,7 @@ static int nfs_idmap_init_keyring(void)
 	return ret;
 }
 
-static void nfs_idmap_quit_keyring(void)
+void nfs_idmap_quit(void)
 {
 	key_revoke(id_resolver_cache->thread_keyring);
 	unregister_key_type(&key_type_id_resolver);
@@ -492,16 +492,6 @@ nfs_idmap_delete(struct nfs_client *clp)
 	kfree(idmap);
 }
 
-int nfs_idmap_init(void)
-{
-	return nfs_idmap_init_keyring();
-}
-
-void nfs_idmap_quit(void)
-{
-	nfs_idmap_quit_keyring();
-}
-
 static int nfs_idmap_prepare_message(char *desc, struct idmap *idmap,
 				     struct idmap_msg *im,
 				     struct rpc_pipe_msg *msg)