usb-ehci: drop unused num-ports state member

Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb-ehci.c

@@ -373,7 +373,6 @@ struct EHCIState {
     qemu_irq irq;
     target_phys_addr_t mem_base;
     int mem;
-    int num_ports;
 
     /* properties */
     uint32_t freq;