usb-ccid: advertise SELF_POWERED

Before commit ed5a83dd each device
provided it's own response to USB_REQ_GET_STATUS, but after it that
response was based on bmAttributes, which was errounously set for
usb-ccid as 0xa0 and not 0xe0.
Signed-off-by: NAlon Levy <alevy@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb-ccid.c

@@ -447,7 +447,7 @@ static const USBDescDevice desc_device = {
         {
             .bNumInterfaces        = 1,
             .bConfigurationValue   = 1,
-            .bmAttributes          = 0xa0,
+            .bmAttributes          = 0xe0,
             .bMaxPower             = 50,
             .nif = 1,
             .ifs = &desc_iface0,