[kcs]compatible with other components

Many existed openbmc components use hard code
"org.openbmc.HostIpmi" to locate service.
In order to make compatible, make '--i' optional.
When specified, kcsbridge will use prefix in dbus name and objpath.
If not, default dbus name "org.openbmc.HostIpmi" will be used.

Change-Id: I87a8e4bd05f60d953df0a550dc633c50c6b8f537
Signed-off-by: Jia, Chunhui <chunhui.jia@linux.intel.com>
diff --git a/kcsbridged.service b/kcsbridged.service
index cac223f..20b75ec 100644
--- a/kcsbridged.service
+++ b/kcsbridged.service
@@ -1,10 +1,10 @@
 [Unit]
-Description=KCS Bridge Daemon
+Description=KCS Bridge Daemon(Sample service file)
 
 [Service]
 Type=dbus
 BusName=org.openbmc.HostIpmi
-ExecStart=/bin/kcsbridged
+ExecStart=/bin/kcsbridged --d="/dev/ipmi-kcs3"
 Restart=on-abort
 
 [Install]