QThread::setPriority() Warn about invalid parameter on all platforms

InheritPriority may not be set, but the warning only occurs on Windows.
Move the warning to the public class.

Change-Id: I51d401300f840e4c1396c2c30182e49ed45d60d2
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
Reviewed-by: Christian Tismer <tismer@stackless.com>
Reviewed-by: David Faure <david.faure@kdab.com>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/corelib/thread/qthread.cpp

@@ -614,7 +614,7 @@ void QThread::run()
     priority.
 
     The \a priority argument can be any value in the \c
-    QThread::Priority enum except for \c InheritPriorty.
+    QThread::Priority enum except for \c InheritPriority.
 
     The effect of the \a priority parameter is dependent on the
     operating system's scheduling policy. In particular, the \a priority
@@ -626,6 +626,10 @@ void QThread::run()
 */
 void QThread::setPriority(Priority priority)
 {
+    if (priority == QThread::InheritPriority) {
+        qWarning("QThread::setPriority: Argument cannot be InheritPriority");
+        return;
+    }
     Q_D(QThread);
     QMutexLocker locker(&d->mutex);
     if (!d->running) {

src/corelib/thread/qthread_win.cpp

@@ -715,9 +715,7 @@ void QThreadPrivate::setPriority(QThread::Priority threadPriority)
         prio = THREAD_PRIORITY_TIME_CRITICAL;
         break;
 
-    case QThread::InheritPriority:
     default:
-        qWarning("QThread::setPriority: Argument cannot be InheritPriority");
         return;
     }