Fix out of tree build with hardcoded tables

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@21228 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/mdct_tablegen.h

@@ -35,7 +35,7 @@ SINETABLE(1024);
 SINETABLE(2048);
 SINETABLE(4096);
 #else
-#include "mdct_tables.h"
+#include "libavcodec/mdct_tables.h"
 #endif
 
 SINETABLE_CONST float * const ff_sine_windows[] = {