op-pdbg-host-control: Order services against obmc targets

Remove sequencing against Witherspoon-specific services from pdbg host
services.
Add sequencing against obmc systemd targets.
Shorten descriptions in pdbg control services.

Signed-off-by: Xo Wang <xow@google.com>
Change-Id: I4d2f55c639f6b3095bdb36fe6161ccc9e2032eec
diff --git a/common/recipes-phosphor/host/op-pdbg-host-control/start_host@.service b/common/recipes-phosphor/host/op-pdbg-host-control/start_host@.service
index dbf6021..13f7c3b 100644
--- a/common/recipes-phosphor/host/op-pdbg-host-control/start_host@.service
+++ b/common/recipes-phosphor/host/op-pdbg-host-control/start_host@.service
@@ -1,7 +1,11 @@
 [Unit]
-Description=Use pdbg to send putcfam command to start IPL
-Wants=vcs_on@.service
-After=vcs_on@.service
+Description=Start host%i SBE (pdbg)
+After=obmc-host-start-pre@%i.target
+Wants=obmc-host-start@%i.target
+Before=obmc-host-start@%i.target
+Before=obmc-host-started@%i.target
+Wants=obmc-power-on@%i.target
+After=obmc-power-on@%i.target
 Conflicts=obmc-chassis-stop@%i.target
 
 [Service]