The USB tablet should not claim boot protocol support.

The USB tablet advertises that it supports the "boot" protocol.
However, its reports aren't "boot" protocol compatible.  So, it
shouldn't claim that.
Signed-off-by: NKevin O'Connor <kevin@koconnor.net>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb-hid.c

@@ -142,7 +142,6 @@ static const USBDescIface desc_iface_tablet = {
     .bInterfaceNumber              = 0,
     .bNumEndpoints                 = 1,
     .bInterfaceClass               = USB_CLASS_HID,
-    .bInterfaceSubClass            = 0x01, /* boot */
     .bInterfaceProtocol            = 0x02,
     .ndesc                         = 1,
     .descs = (USBDescOther[]) {