clang-tidy: Enable modernize-use-override check

This check adds override (introduced in C++11) to overridden
virtual functions and removes virtual from those functions as it
is not required.

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: I7ce6bf641dabf4d325a29a1b641e58beac6885bd
diff --git a/test/utest-group-priority.cpp b/test/utest-group-priority.cpp
index 73b3747..f47e5f2 100644
--- a/test/utest-group-priority.cpp
+++ b/test/utest-group-priority.cpp
@@ -17,7 +17,7 @@
     {
         // Nothing here
     }
-    ~LedTest() = default;
+    ~LedTest() override = default;
 };
 
 static void assertMap(std::map<LedName, Layout::LedAction> map,