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/qnx/qnxdevice.cpp

@@ -60,7 +60,7 @@ class QnxPortsGatheringMethod : public PortsGatheringMethod
     // used to be fixed. These two can now be matched to each other.
     Runnable runnable(QAbstractSocket::NetworkLayerProtocol protocol) const override
     {
-        Q_UNUSED(protocol);
+        Q_UNUSED(protocol)
         Runnable runnable;
         runnable.executable = FileName::fromString("netstat");
         runnable.commandLineArguments = "-na";