eventlog: Added comment for powerd_suspend dependency

powerd_suspend calls the eventlog script to update the mosys eventlog
snapshot on every resume.  Added comment noting this dependency.

TEST=do a suspend-resume cycle. Then open up "eventlog" under
chrome://system.  The last entry in eventlog should correspond
to the resume that just happened.

Change-Id: I8e0d337554c590f31af1d0ce5d9cd0d86a2d5a87
Reviewed-on: https://gerrit.chromium.org/gerrit/43303
Reviewed-by: Daniel Erat <derat@chromium.org>
Commit-Queue: Sameer Nanda <snanda@chromium.org>
Tested-by: Sameer Nanda <snanda@chromium.org>
diff --git a/scripts/eventlog b/scripts/eventlog
index a0464ee..2456e24 100755
--- a/scripts/eventlog
+++ b/scripts/eventlog
@@ -4,6 +4,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+# NOTE: This script is invoked by powerd_suspend each time the system resumes.
+# If any changes are made to this script, remember to update powerd_suspend,
+# as needed.
 # File to store firmware information derived from firmware event log