greybus: core: add MODULE uevent var for all control devices

The new ctrl device under interface is missing a MODULE uevent var,
add it.

Testing Done:
cat 'uevent' from ctrl device.
$ cat 1-3.3.ctrl/uevent
DEVTYPE=greybus_control
BUS=1
MODULE=3
INTERFACE=3
GREYBUS_ID=fffe0001/ffee0011
Signed-off-by: Sandeep Patil <sspatil@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/core.c

@@ -103,6 +103,7 @@ static int greybus_uevent(struct device *dev, struct kobj_uevent_env *env)
 	} else if (is_gb_control(dev)) {
 		control = to_gb_control(dev);
 		intf = control->intf;
+		module = intf->module;
 		hd = intf->hd;
 	} else if (is_gb_bundle(dev)) {
 		bundle = to_gb_bundle(dev);