init.qcom.rc: Add a custom shutdown trigger to kill rmtfs am: 66a926c714 am: d3b26ba98f

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/1331554

Change-Id: I93c9fbbc08300e08aed19d527a66a166987c131a
diff --git a/qcom/init.qcom.rc b/qcom/init.qcom.rc
index 5867179..4319569 100644
--- a/qcom/init.qcom.rc
+++ b/qcom/init.qcom.rc
@@ -56,3 +56,6 @@
     write /sys/class/firmware/timeout 1
     start tqftpserv
     start rmtfs
+
+on shutdown
+    stop rmtfs