host_monitor_app: Updating checkpoint name of S0 and S5

Update the name to meet the requirement.

Tested:
```
bmc$ busctl call --verbose com.google.gbmc.boot_time_monitor /xyz/openbmc_project/time/boot/host0 xyz.openbmc_project.Time.Boot.Checkpoint GetCheckpointList
MESSAGE "a(sxx)" {
        ARRAY "(sxx)" {

                STRUCT "sxx" {
                        STRING "To_Off";
                        INT64 1704350090260;
                        INT64 2211580;
                };
                STRUCT "sxx" {
                        STRING "Off";
                        INT64 1704350098511;
                        INT64 2219830;
                };
        };
};

```

Google-Bug-Id: 296787899
Google-Bug-Id: 296791279
Change-Id: Ie50d302d3b3e851a8c4db09eab7acc1cf5718bb3
Signed-off-by: Michael Shen <gpgpgp@google.com>
1 file changed