Add brief description to example interfaces

Change-Id: I69ab3de21da08e320bccd122d1f194691784e7fd
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/example/interfaces.yaml b/example/interfaces.yaml
index 56b6198..d48bdef 100644
--- a/example/interfaces.yaml
+++ b/example/interfaces.yaml
@@ -1,2 +1,5 @@
+# The interfaces file defines which interfaces
+# will be processed by the Notify method.
+
 - xyz.openbmc_project.Example.Iface1
 - xyz.openbmc_project.Example.Iface2