greybus: add bundle class to the bundle uevent

When bundles are added and then removed, we have a race where we go to
read the sysfs file, but it is now for a different bundle than the
uevent was originally for.  So add the bundle class to the uevent so we
"know" what the correct bundle class was.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/core.c

@@ -125,6 +125,8 @@ static int greybus_uevent(struct device *dev, struct kobj_uevent_env *env)
 
 		if (add_uevent_var(env, "BUNDLE=%u", bundle->id))
 			return -ENOMEM;
+		if (add_uevent_var(env, "BUNDLE_CLASS=%02x", bundle->class))
+			return -ENOMEM;
 	}
 
 	return 0;