controller: Fix readability-braces-around-statements

```
/home/andrew/src/openbmc/phosphor-led-sysfs/build/../controller.cpp:75:36: error: statement should be inside braces [readability-braces-around-statements,-warnings-as-errors]
    if (!ledDescr.function.empty())
                                   ^
                                    {
/home/andrew/src/openbmc/phosphor-led-sysfs/build/../controller.cpp:77:33: error: statement should be inside braces [readability-braces-around-statements,-warnings-as-errors]
    if (!ledDescr.color.empty())
                                ^
                                 {
```

Change-Id: I2f1a487638786885ff4ebd9aba26e22c1b943fe1
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/controller.cpp b/controller.cpp
index cce3f10..34cb056 100644
--- a/controller.cpp
+++ b/controller.cpp
@@ -73,9 +73,13 @@
     std::vector<std::string> words;
     words.emplace_back(ledDescr.devicename);
     if (!ledDescr.function.empty())
+    {
         words.emplace_back(ledDescr.function);
+    }
     if (!ledDescr.color.empty())
+    {
         words.emplace_back(ledDescr.color);
+    }
     return boost::join(words, "_");
 }