of: unittest: Fix mispick of testcase data

Ensure we have the data we're going to use for the changeset tests.

Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/of/unittest-data/testcases.dts b/drivers/of/unittest-data/testcases.dts
index d26b96a..16c9c87 100644
--- a/drivers/of/unittest-data/testcases.dts
+++ b/drivers/of/unittest-data/testcases.dts
@@ -1,4 +1,14 @@
 /dts-v1/;
+/ {
+        testcase-data {
+                changeset {
+                        prop-update = "hello";
+                        prop-remove = "world";
+                        node-remove {
+                        };
+                };
+        };
+};
 #include "tests-phandle.dtsi"
 #include "tests-interrupts.dtsi"
 #include "tests-match.dtsi"