hid: Implement HidD_FlushQueue().

dlls/hid/hid.spec

-@ stub HidD_FlushQueue
+@ stdcall HidD_FlushQueue(ptr)
 @ stdcall HidD_FreePreparsedData(ptr)
 @ stdcall HidD_GetAttributes(long ptr)
 @ stub HidD_GetConfiguration

dlls/hid/hidd.c

@@ -163,3 +163,9 @@ BOOLEAN WINAPI HidD_GetIndexedString(HANDLE file, ULONG index, void *buffer, ULO
     TRACE("file %p, index %u, buffer %p, length %u.\n", file, index, buffer, length);
     return sync_ioctl(file, IOCTL_HID_GET_INDEXED_STRING, &index, sizeof(index), buffer, length);
 }
+
+BOOLEAN WINAPI HidD_FlushQueue(HANDLE file)
+{
+    TRACE("file %p.\n", file);
+    return sync_ioctl(file, IOCTL_HID_FLUSH_QUEUE, NULL, 0, NULL, 0);
+}

include/ddk/hidsdi.h

@@ -34,6 +34,7 @@ typedef struct _HIDD_ATTRIBUTES {
   USHORT VersionNumber;
 } HIDD_ATTRIBUTES, *PHIDD_ATTRIBUTES;
 
+BOOLEAN WINAPI HidD_FlushQueue(HANDLE file);
 BOOLEAN WINAPI HidD_GetFeature(HANDLE HidDeviceObject, PVOID ReportBuffer, ULONG ReportBufferLength);
 void WINAPI HidD_GetHidGuid(LPGUID guid);
 BOOLEAN WINAPI HidD_GetIndexedString(HANDLE file, ULONG index, void *buffer, ULONG length);