i2c: immediately mark ourselves as registered

Mark the i2c bus as registered right after the the bus_register call,
not at the end of init. Otherwise, we can't register our own dummy
driver.

Reported-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Fixes: 95026658c46ea2 ("i2c: do not use internal data from driver core")

drivers/i2c/i2c-core.c

@@ -2105,6 +2105,9 @@ static int __init i2c_init(void)
 	retval = bus_register(&i2c_bus_type);
 	if (retval)
 		return retval;
+
+	is_registered = true;
+
 #ifdef CONFIG_I2C_COMPAT
 	i2c_adapter_compat_class = class_compat_register("i2c-adapter");
 	if (!i2c_adapter_compat_class) {
@@ -2119,7 +2122,6 @@ static int __init i2c_init(void)
 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
 		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
 
-	is_registered = true;
 	return 0;
 
 class_err:
@@ -2127,6 +2129,7 @@ class_err:
 	class_compat_unregister(i2c_adapter_compat_class);
 bus_err:
 #endif
+	is_registered = false;
 	bus_unregister(&i2c_bus_type);
 	return retval;
 }