aacdec: Fix warning: initialization from incompatible pointer type

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/aacdec.c

@@ -2627,7 +2627,7 @@ static int aac_decode_frame_int(AVCodecContext *avctx, void *data,
 
     if (multiplier) {
         int side_size;
-        uint32_t *side = av_packet_get_side_data(avpkt, AV_PKT_DATA_SKIP_SAMPLES, &side_size);
+        const uint8_t *side = av_packet_get_side_data(avpkt, AV_PKT_DATA_SKIP_SAMPLES, &side_size);
         if (side && side_size>=4)
             AV_WL32(side, 2*AV_RL32(side));
     }