Fix FSF postal address.

Originally committed as revision 7638 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/dtsdec.c

@@ -16,7 +16,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with FFmpeg; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifdef HAVE_AV_CONFIG_H