Warn on node name unit-address presence/absence mismatch

ePAPR 1.1 section 2.2.1.1 "Node Name Requirements" specifies that any
node that has a reg property must include a unit address in its name
with value matching the first entry in its reg property. Conversely, if
a node does not have a reg property, the node name must not include a
unit address. Also allow ranges property as it is deemed valid, but ePAPR
is not clear about it.

Implement a check for this. The code doesn't validate the format of the
unit address; ePAPR implies this may vary from (containing bus) binding
to binding, so doing so would be much more complex.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
[robh: also allow non-empty ranges]
Signed-off-by: Rob Herring <robh@kernel.org>
[moved new test in check_table]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

tests/unit-addr-without-reg.dts

@@ -0,0 +1,9 @@
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	node@1 {
+	};
+};