meta-openpower: match start_host Install to p9-host-start recipe

The recipe uses a "requires" template against startmin, so adjust the
service file Install directive to match in order to avoid confusion.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I62e0ad1efc0d9a7028a00cd0aaa01ce3bbb9ef40
diff --git a/meta-openpower/recipes-phosphor/host/op-host-control/start_host@.service b/meta-openpower/recipes-phosphor/host/op-host-control/start_host@.service
index bfe8dbe..d6870d2 100644
--- a/meta-openpower/recipes-phosphor/host/op-host-control/start_host@.service
+++ b/meta-openpower/recipes-phosphor/host/op-host-control/start_host@.service
@@ -17,4 +17,4 @@
 RemainAfterExit=yes
 
 [Install]
-WantedBy=obmc-host-start@%i.target
+RequiredBy=obmc-host-startmin@%i.target