Avoid warning on empty expressions

For some reason, Q_UNUSED includes already a semicolon, adding one
on the user side creates an additional empty statement.

Change-Id: I9c5e8fac381345a60792cb75e2938fd53958d3b0
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/debugger/registerhandler.cpp

@@ -434,7 +434,7 @@ public:
     {
         //return column == 1 ? Qt::ItemIsSelectable|Qt::ItemIsEnabled|Qt::ItemIsEditable
         //                   : Qt::ItemIsSelectable|Qt::ItemIsEnabled;
-        Q_UNUSED(column);
+        Q_UNUSED(column)
         return Qt::ItemIsSelectable|Qt::ItemIsEnabled;
     }