meta-facebook: harma: revise bios update script

Use force off to shut down the host and reduce sleep time.

Change-Id: I7a8d621e09cf18bbb47933365cdb4c8785ecbd9a
Signed-off-by: Peter Yin <peter.yin@quantatw.com>
diff --git a/meta-facebook/meta-harma/recipes-phosphor/flash/phosphor-software-manager/bios-update.sh b/meta-facebook/meta-harma/recipes-phosphor/flash/phosphor-software-manager/bios-update.sh
index 25bde6d..e29ca90 100755
--- a/meta-facebook/meta-harma/recipes-phosphor/flash/phosphor-software-manager/bios-update.sh
+++ b/meta-facebook/meta-harma/recipes-phosphor/flash/phosphor-software-manager/bios-update.sh
@@ -30,10 +30,10 @@
 echo "Bios upgrade started at $(date)"
 
 #Power off host server.
-echo "Power off host server"
-obmcutil poweroff
+echo "Power off host server by force off"
+obmcutil chassisoff
 
-sleep 15
+sleep 10
 if [ "$(power_status)" != "off" ];
 then
     echo "Host server didn't power off"