Make default_correlation array const since it is never modified.

Originally committed as revision 19924 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/wmaprodata.h

@@ -591,7 +591,7 @@ static const float default_decorrelation_matrices[] = {
 /**
  * @brief default decorrelation matrix offsets
  */
-static const float *default_decorrelation[] = {
+static const float * const default_decorrelation[] = {
     NULL,
     &default_decorrelation_matrices[0],
     &default_decorrelation_matrices[1],