usb-hid: remove usb_hid_datain_cb

No users left, all migrated over to hw/hid.[ch].
Yea!  Zap it!
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb-hid.c

@@ -45,8 +45,6 @@
 typedef struct USBHIDState {
     USBDevice dev;
     HIDState hid;
-    void *datain_opaque;
-    void (*datain)(void *);
 } USBHIDState;
 
 enum {
@@ -362,10 +360,6 @@ static void usb_hid_changed(HIDState *hs)
 {
     USBHIDState *us = container_of(hs, USBHIDState, hid);
 
-    if (us->datain) {
-        us->datain(us->datain_opaque);
-    }
-
     usb_wakeup(&us->dev);
 }
 
@@ -533,14 +527,6 @@ static int usb_keyboard_initfn(USBDevice *dev)
     return usb_hid_initfn(dev, HID_KEYBOARD);
 }
 
-void usb_hid_datain_cb(USBDevice *dev, void *opaque, void (*datain)(void *))
-{
-    USBHIDState *s = (USBHIDState *)dev;
-
-    s->datain_opaque = opaque;
-    s->datain = datain;
-}
-
 static const VMStateDescription vmstate_usb_ptr = {
     .name = "usb-ptr",
     .version_id = 1,

hw/usb.h

@@ -316,9 +316,6 @@ USBDevice *usb_host_device_open(const char *devname);
 int usb_host_device_close(const char *devname);
 void usb_host_info(Monitor *mon);
 
-/* usb-hid.c */
-void usb_hid_datain_cb(USBDevice *dev, void *opaque, void (*datain)(void *));
-
 /* usb-bt.c */
 USBDevice *usb_bt_init(HCIInfo *hci);