Adding Bazel support for YANG models.

Change-Id: Icdb620bdb99ae9eeb042a84a8ca7563588c813c1
diff --git a/models/ietf/BUILD b/models/ietf/BUILD
new file mode 100644
index 0000000..9197c54
--- /dev/null
+++ b/models/ietf/BUILD
@@ -0,0 +1,7 @@
+load("//tools/build/bazel:yang.bzl", "yang_model")
+
+yang_model (
+    app_name = "org.onosproject.models.ietf",
+    title = "IETF YANG Models",
+    custom_registrator = False,
+)