driver core: bus: Fix double free in driver API bus_register()

For bus_register(), any error which happens after kset_register() will
cause that @priv are freed twice, fixed by setting @priv with NULL after
the first free.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20240727-bus_register_fix-v1-1-fed8dd0dba7a@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/bus.c

@@ -922,6 +922,8 @@ bus_devices_fail:
 	bus_remove_file(bus, &bus_attr_uevent);
 bus_uevent_fail:
 	kset_unregister(&priv->subsys);
+	/* Above kset_unregister() will kfree @priv */
+	priv = NULL;
 out:
 	kfree(priv);
 	return retval;