vmmouse: fix queue_size field initialization

Initialize the field queue_size, dropped by
91c9e091.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

hw/vmmouse.c

@@ -253,6 +253,7 @@ static void vmmouse_reset(DeviceState *d)
     VMMouseState *s = container_of(d, VMMouseState, dev.qdev);
 
     s->status = 0xffff;
+    s->queue_size = VMMOUSE_QUEUE_SIZE;
 }
 
 static int vmmouse_initfn(ISADevice *dev)