FruDevice: update service to always restart

Entity Manager depends on FruDevice service to scan and then load
configurations. Update FruDevice service to always restart on failure.
Set restartsec to 5 seconds.

Tested:
Service auto restart when the process is killed.

Signed-off-by: Zhikui Ren <zhikui.ren@intel.com>
Change-Id: I9c408c8d89a27bac0d7ae2ea6c419e1f544a222f
diff --git a/service_files/xyz.openbmc_project.FruDevice.service b/service_files/xyz.openbmc_project.FruDevice.service
index 97080c4..8f5c00f 100644
--- a/service_files/xyz.openbmc_project.FruDevice.service
+++ b/service_files/xyz.openbmc_project.FruDevice.service
@@ -4,6 +4,8 @@
 
 [Service]
 ExecStart=/usr/bin/fru-device
+Restart=always
+RestartSec=5
 Type=simple
 
 [Install]