Translate -mfpu=vfpv3 for TMS470

Originally committed as revision 21357 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -1692,6 +1692,7 @@ elif $cc -version 2>/dev/null | grep -q TMS470; then
                     ;;
                 -mfpu=neon)     echo --float_support=vfpv3 --neon ;;
                 -mfpu=vfp)      echo --float_support=vfpv2        ;;
+                -mfpu=vfpv3)    echo --float_support=vfpv3        ;;
                 -msoft-float)   echo --float_support=vfplib       ;;
                 -Os)            echo -O3 -mf=2                    ;;
                 -O[0-3])        echo $flag -mf=5                  ;;