openpower: Hold off MPIPL procedure until OCC disabled

The OCC disable procedure starts, but does not always complete before
the MPIPL procedure starts. This can cause SRAM write failures which
will end up terminating openpower-occ-control.

This fix will delay starting the MPIPL procedure util OCC disable
completes.

Signed-off-by: Chris Cain <cjcain@us.ibm.com>
Change-Id: I615dcc70a57501172097efd5a37fe9200b3d094e
diff --git a/meta-openpower/recipes-phosphor/occ/openpower-occ-control/op-occ-disable@.service b/meta-openpower/recipes-phosphor/occ/openpower-occ-control/op-occ-disable@.service
index 0179a50..e18d91c 100644
--- a/meta-openpower/recipes-phosphor/occ/openpower-occ-control/op-occ-disable@.service
+++ b/meta-openpower/recipes-phosphor/occ/openpower-occ-control/op-occ-disable@.service
@@ -1,6 +1,7 @@
 [Unit]
 Description=OpenPOWER OCC Active Disable
 Before=obmc-host-stop-pre@%i.target
+Before=op-enter-mpreboot@%i.service
 Conflicts=op-occ-enable@%i.service
 
 [Service]