controller: Fix readability-identifier-naming

```
/home/andrew/src/openbmc/phosphor-led-sysfs/build/../controller.cpp:27:13: error: invalid case style for function 'ExitWithError' [readability-identifier-naming,-warnings-as-errors]
static void ExitWithError(const char* err, char** argv)
            ^~~~~~~~~~~~~
            exitWithError
```

Change-Id: I9fc779fcec82c00cb2168e07703a51548990f066
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
1 file changed