winex11.drv: Remove unneeded address-of operator from function name

[Andrew Talbot]

Changelog:
    winex11.drv: Remove unneeded address-of operator from function name.

diff --git a/dlls/winex11.drv/clipboard.c b/dlls/winex11.drv/clipboard.c
index cda8f9e..caf2406 100644
--- a/dlls/winex11.drv/clipboard.c
+++ b/dlls/winex11.drv/clipboard.c
@@ -2574,7 +2574,7 @@ int CDECL X11DRV_AcquireClipboard(HWND hWndClipWindow)
     else
     {
         HANDLE event = CreateEventW(NULL, FALSE, FALSE, NULL);
-        selectionThread = CreateThread(NULL, 0, &selection_thread_proc, event, 0, NULL);
+        selectionThread = CreateThread(NULL, 0, selection_thread_proc, event, 0, NULL);
 
         if (!selectionThread)
         {