phosphor-host-condition-gpio: enable multi-host support

The current implementation fails with:

```
[   18.664351] systemd[1]: phosphor-host-condition-gpio@1.service: Two services allocated for the same bus name xyz.openbmc_project.State.HostCondition.Gpio, refusing operation.
```

Add the host id into the reserved bus name to avoid collisions.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ia4f291d20df913d3f506d976a961a770a81724fc
diff --git a/host_condition_gpio/phosphor-host-condition-gpio@.service b/host_condition_gpio/phosphor-host-condition-gpio@.service
index fa70e3e..19e41c5 100644
--- a/host_condition_gpio/phosphor-host-condition-gpio@.service
+++ b/host_condition_gpio/phosphor-host-condition-gpio@.service
@@ -5,7 +5,7 @@
 Restart=always
 ExecStart=/usr/bin/phosphor-host-condition-gpio %i
 Type=dbus
-BusName=xyz.openbmc_project.State.HostCondition.Gpio
+BusName=xyz.openbmc_project.State.HostCondition.Gpio%i
 
 [Install]
 WantedBy=multi-user.target