Change the service type from oneshot to simple

With oneshot type will block until the running process exists,
however the fru-device does not exit,
this causes the service status is always in running

Change-Id: Ibb246de21a6a2433549f09241d540348eb93870b
Signed-off-by: Yong Li <yong.b.li@linux.intel.com>
diff --git a/service_files/xyz.openbmc_project.FruDevice.service b/service_files/xyz.openbmc_project.FruDevice.service
index 7d69c31..4ed78f8 100644
--- a/service_files/xyz.openbmc_project.FruDevice.service
+++ b/service_files/xyz.openbmc_project.FruDevice.service
@@ -6,7 +6,7 @@
 
 [Service]
 ExecStart=/usr/sbin/fru-device
-Type=oneshot
+Type=simple
 
 [Install]
 WantedBy=basic.target