Starting with DT compiler version 1.4.6 (included since v2018.07.0) one gets
warnings

  <node>: node has a reg or ranges property, but no unit name

if the first address field of a reg-property is not taken as the unit name for
its parent node.

Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>