Revert "avutil: make some tables visible again"

This reverts commit def8c94699.

After the major bump this is no longer necessary.

libavutil/libavutil.v

@@ -1,4 +1,4 @@
 LIBAVUTIL_$MAJOR {
-        global: av*; ff_*_tab;
+        global: av*;
         local: *;
 };