Fix jerky animations in Qt Quick for iOS.

This will make Qt Quick use consistent timing which
prepares animation frames for the time they go to
screen, rather than the current time at the time of the
animation tick, which can be quite jerky in many situations.

Change-Id: I1bbd4394db0c757553ee406d416fccb3ef937db8
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

src/plugins/platforms/ios/qiosintegration.mm

@@ -101,6 +101,8 @@ QIOSIntegration::~QIOSIntegration()
 bool QIOSIntegration::hasCapability(Capability cap) const
 {
     switch (cap) {
+    case BufferQueueingOpenGL:
+        return true;
     case OpenGL:
     case ThreadedOpenGL:
         return true;