phosphor-discover-system-state: improve service description

A multi-host system currently starts 8 instances of this service
with less than useful service descriptions.  Improve the description
to include the host in question.

```
[  OK  ] Started Reboot If Enabled.
[  OK  ] Started Reboot If Enabled.
[  OK  ] Started Reboot If Enabled.
[  OK  ] Started Reboot If Enabled.
[  OK  ] Started Reboot If Enabled.
[  OK  ] Started Reboot If Enabled.
[  OK  ] Started Reboot If Enabled.
[  OK  ] Started Reboot If Enabled.
```

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I3867c30dedf12937db8f96df2d4b34d715828f05
diff --git a/service_files/phosphor-discover-system-state@.service b/service_files/phosphor-discover-system-state@.service
index 3f665f9..2ac277e 100644
--- a/service_files/phosphor-discover-system-state@.service
+++ b/service_files/phosphor-discover-system-state@.service
@@ -1,5 +1,5 @@
 [Unit]
-Description=Reboot If Enabled
+Description=Reboot Host %i If Enabled
 Wants=mapper-wait@-xyz-openbmc_project-control-host%i-power_restore_policy.service
 After=mapper-wait@-xyz-openbmc_project-control-host%i-power_restore_policy.service
 Wants=mapper-wait@-xyz-openbmc_project-state-host%i.service