op-power-start: ensure runs after pre power on target

If no one else has started this synchronization target before this
service starts then it will run without waiting since there is no Wants
clause. Add the Wants clause to ensure proper synchronization occurs.

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: I5db6a5800d5456efd97d0f8c2eabd9113d725370
diff --git a/meta-phosphor/recipes-phosphor/chassis/obmc-op-control-power/op-power-start@.service b/meta-phosphor/recipes-phosphor/chassis/obmc-op-control-power/op-power-start@.service
index c1de92f..82b7938 100644
--- a/meta-phosphor/recipes-phosphor/chassis/obmc-op-control-power/op-power-start@.service
+++ b/meta-phosphor/recipes-phosphor/chassis/obmc-op-control-power/op-power-start@.service
@@ -2,6 +2,7 @@
 Description=Start Power%i
 Wants=obmc-power-start@%i.target
 Before=obmc-power-start@%i.target
+Wants=obmc-power-start-pre@%i.target
 After=obmc-power-start-pre@%i.target
 After=obmc-fan-control.target
 Wants=mapper-wait@-org-openbmc-control-power%i.service