gdiplus: Void function should not return a value

[Andrew Talbot]

Changelog:
    gdiplus: Void function should not return a value.

diff --git a/dlls/gdiplus/gdiplus.c b/dlls/gdiplus/gdiplus.c
index c9c3102..35caad8 100644
--- a/dlls/gdiplus/gdiplus.c
+++ b/dlls/gdiplus/gdiplus.c
@@ -109,7 +109,7 @@ GpStatus WINAPI GdiplusNotificationHook(ULONG_PTR *token)
 void WINAPI GdiplusNotificationUnhook(ULONG_PTR token)
 {
     FIXME("%ld\n", token);
-    return NotificationUnhook(token);
+    NotificationUnhook(token);
 }
 
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