Suppress warnings on overlay fragments

Overlay fragments are traditionally named "fragment@NNN" but don't have
have a 'reg' property, amongst other differences from normal nodes.  Really
we should treat overlay fragments fundamentally differently, but for the
moment, suppress the common warnings about the fragment names with this
simple hack.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

checks.c

@@ -317,6 +317,11 @@ static void check_unit_address_vs_reg(struct check *c, struct dt_info *dti,
 	const char *unitname = get_unitname(node);
 	struct property *prop = get_property(node, "reg");
 
+	if (get_subnode(node, "__overlay__")) {
+		/* HACK: Overlay fragments are a special case */
+		return;
+	}
+
 	if (!prop) {
 		prop = get_property(node, "ranges");
 		if (prop && !prop->val.len)