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 <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/nfs4idmap.c

···
 	.read		= user_read,
 };
 
-static int nfs_idmap_init_keyring(void)
+int nfs_idmap_init(void)
 {
 	struct cred *cred;
 	struct key *keyring;
···
 	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);
···
 			&idmap->idmap_pdo);
 	rpc_destroy_pipe_data(idmap->idmap_pipe);
 	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,