add CtsBackupTestCases to presubmit for cts device tests

Bug: 136460995

Test: atest CtsBackupTestCases
Change-Id: I03ae657a92c8ba5dcd72845b39b4a4e98d8b5074
diff --git a/tests/backup/TEST_MAPPING b/tests/backup/TEST_MAPPING
new file mode 100644
index 0000000..4e5beb0
--- /dev/null
+++ b/tests/backup/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+      "name": "CtsBackupTestCases"
+    }
+  ]
+}