Xext: xv: fix redefinition of typedef 'XvPortNotifyPtr'

In file included from ../Xext/xvmc.c:14:
  ../Xext/xvdix_priv.h:31:21: warning: redefinition of typedef 'XvPortNotifyPtr' is a C11 feature [-Wtypedef-redefinition]
     31 | } XvPortNotifyRec, *XvPortNotifyPtr;
        |                     ^
  ../Xext/xvdix.h:73:34: note: previous definition is here
     73 | typedef struct _XvPortNotifyRec *XvPortNotifyPtr;
        |                                  ^
  1 warning generated.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

Xext/xvdix_priv.h

@@ -28,7 +28,7 @@ typedef struct _XvPortNotifyRec {
     struct _XvPortNotifyRec *next;
     ClientPtr client;
     unsigned long id;
-} XvPortNotifyRec, *XvPortNotifyPtr;
+} XvPortNotifyRec;
 
 extern int XvReqCode;
 extern int XvErrorBase;