aacenc: Remove energy 'normalization' modification from the 3GPP psymodel

This greatly improves bitrate handling. You will now get within a few
kbps of your requested bitrate instead of 20-40kbps higher.

There is absolutely no analog to this line in the 3GPP spec, that I
can find.

patch by Nathan Caldwell saintdev (at) gmail

Originally committed as revision 25589 to svn://svn.ffmpeg.org/ffmpeg/trunk