ehci: drop pointless warn_report for guest bugs.

We have a tracepoint at the same place which can be enabled if needed.

Buglink: https://bugzilla.redhat.com//show_bug.cgi?id=1859236
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200722072613.10390-1-kraxel@redhat.com>

hw/usb/hcd-ehci.c

@@ -352,7 +352,6 @@ static void ehci_trace_sitd(EHCIState *s, hwaddr addr,
 static void ehci_trace_guest_bug(EHCIState *s, const char *message)
 {
     trace_usb_ehci_guest_bug(message);
-    warn_report("%s", message);
 }
 
 static inline bool ehci_enabled(EHCIState *s)