avcodec/g723_1dec: Fix invalid shift

Fixes the FATE-tests g723_1-dec-1, g723_1-dec-2 and g723_1-dec-4.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 54e1efda6d)

libavcodec/g723_1dec.c

@@ -1012,7 +1012,7 @@ static int g723_1_decode_frame(AVCodecContext *avctx, void *data,
             formant_postfilter(p, lpc, p->audio, out);
         } else { // if output is not postfiltered it should be scaled by 2
             for (i = 0; i < FRAME_LEN; i++)
-                out[i] = av_clip_int16(p->audio[LPC_ORDER + i] << 1);
+                out[i] = av_clip_int16(2 * p->audio[LPC_ORDER + i]);
         }
     }