amrnbdec: Apply AMR_SAMPLE_SCALE when finishing the decoder output

The output scaling was accidentally removed in rev 22937.

Originally committed as revision 23012 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/amrnbdec.c

@@ -1043,7 +1043,8 @@ static int amrnb_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     }
 
     ff_acelp_apply_order_2_transfer_function(buf_out, buf_out, highpass_zeros,
-                                             highpass_poles, highpass_gain,
+                                             highpass_poles,
+                                             highpass_gain * AMR_SAMPLE_SCALE,
                                              p->high_pass_mem, AMR_BLOCK_SIZE);
 
     /* Update averaged lsf vector (used for fixed gain smoothing).