qxl: Add missing trace.h (fix broken build)

Commit ac86048bcd removed trace.h from
console.h and ignored the fact that qxl-render.c needs this file
(it includes qxl.h which includes console.h which included trace.h).

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

hw/display/qxl-render.c

@@ -20,6 +20,7 @@
  */
 
 #include "qxl.h"
+#include "trace.h"
 
 static void qxl_blit(PCIQXLDevice *qxl, QXLRect *rect)
 {