Fix the boot order of ssifbridged

The ssifbridged should be started after phosphor-ipmi-host service.

Test:
- AC system. Check log to make sure ssifbridged is started after
phosphor-ipmi-host
- Test ipmitool command from Linux.

Signed-off-by: Dung Cao <dung@os.amperecomputing.com>
Change-Id: I53780e38bf1703a4fe1c079572717dd1b12008f0
diff --git a/ssifbridge.service b/ssifbridge.service
index bdd0962..055e0ab 100644
--- a/ssifbridge.service
+++ b/ssifbridge.service
@@ -2,6 +2,7 @@
 Description=Phosphor IPMI SSIF DBus Bridge
 StartLimitBurst=3
 StartLimitIntervalSec=300
+After=phosphor-ipmi-host.service
 
 [Service]
 Restart=always
@@ -13,4 +14,4 @@
 
 [Install]
 WantedBy=multi-user.target
-RequiredBy=
\ No newline at end of file
+RequiredBy=