chassis: fix clang-tidy warning

```
/data0/jenkins/workspace/ci-repository/openbmc/bmcweb/redfish-core/lib/chassis.hpp:130:13: error: loop will run at most once (loop increment never executed) [clang-diagnostic-unreachable-code-loop-increment,-warnings-as-errors]
            for (const auto& service : object.second)
```

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I3d7743115ec31d6f704a857f3e878fa1b7728a60