greybus: interface: remove device_id attribute

The interface device_id attribute is an implementation detail that does
not need to be exported to user space.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/interface.c

@@ -20,14 +20,12 @@ static ssize_t field##_show(struct device *dev,				\
 }									\
 static DEVICE_ATTR_RO(field)
 
-gb_interface_attr(device_id, d);
 gb_interface_attr(vendor_id, x);
 gb_interface_attr(product_id, x);
 gb_interface_attr(vendor_string, s);
 gb_interface_attr(product_string, s);
 
 static struct attribute *interface_attrs[] = {
-	&dev_attr_device_id.attr,
 	&dev_attr_vendor_id.attr,
 	&dev_attr_product_id.attr,
 	&dev_attr_vendor_string.attr,