FAFT: Don't restore the GBB flags for speed-up

Setting up and restoring the GBB flags take a lot of time. For
speed-up purpose, don't restore it.

BUG=None
TEST=Ran a FAFT test to verify nothing broken.

Change-Id: I142d43121c7779d949a730b8efc2c3761b9b728f
Reviewed-on: https://chromium-review.googlesource.com/295771
Commit-Ready: Wai-Hong Tam <waihong@chromium.org>
Tested-by: Wai-Hong Tam <waihong@chromium.org>
Reviewed-by: Shelley Chen <shchen@chromium.org>
diff --git a/server/cros/faft/firmware_test.py b/server/cros/faft/firmware_test.py
index 79d9d86..f10363c 100644
--- a/server/cros/faft/firmware_test.py
+++ b/server/cros/faft/firmware_test.py
@@ -753,7 +753,12 @@
         """Restore GBB flags to their original state."""
         if not self._backup_gbb_flags:
             return
-        self._write_gbb_flags(self._backup_gbb_flags)
+        # Setting up and restoring the GBB flags take a lot of time. For
+        # speed-up purpose, don't restore it.
+        logging.info('***')
+        logging.info('*** Please manually restore the original GBB flags to: '
+                     '0x%x ***', self._backup_gbb_flags)
+        logging.info('***')
         self.unmark_setup_done('gbb_flags')
 
     def setup_tried_fwb(self, tried_fwb):