Bluetooth: Use common error handling code in bt_init()

* Improve jump targets so that a bit of exception handling can be better
  reused at the end of this function.

* Adjust five condition checks.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/af_bluetooth.c

@@ -766,43 +766,39 @@ static int __init bt_init(void)
 		return err;
 
 	err = sock_register(&bt_sock_family_ops);
-	if (err < 0) {
-		bt_sysfs_cleanup();
-		return err;
-	}
+	if (err)
+		goto cleanup_sysfs;
 
 	BT_INFO("HCI device and connection manager initialized");
 
 	err = hci_sock_init();
-	if (err < 0)
-		goto error;
+	if (err)
+		goto unregister_socket;
 
 	err = l2cap_init();
-	if (err < 0)
-		goto sock_err;
+	if (err)
+		goto cleanup_socket;
 
 	err = sco_init();
-	if (err < 0) {
-		l2cap_exit();
-		goto sock_err;
-	}
+	if (err)
+		goto cleanup_cap;
 
 	err = mgmt_init();
-	if (err < 0) {
-		sco_exit();
-		l2cap_exit();
-		goto sock_err;
-	}
+	if (err)
+		goto cleanup_sco;
 
 	return 0;
 
-sock_err:
+cleanup_sco:
+	sco_exit();
+cleanup_cap:
+	l2cap_exit();
+cleanup_socket:
 	hci_sock_cleanup();
-
-error:
+unregister_socket:
 	sock_unregister(PF_BLUETOOTH);
+cleanup_sysfs:
 	bt_sysfs_cleanup();
-
 	return err;
 }