avformat/movenc: Make static packed_size, const static

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

libavformat/movenc.c

@@ -4341,7 +4341,7 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
 
     if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
         /* We must find out how many AMR blocks there are in one packet */
-        static uint16_t packed_size[16] =
+        static const uint16_t packed_size[16] =
             {13, 14, 16, 18, 20, 21, 27, 32, 6, 0, 0, 0, 0, 0, 0, 1};
         int len = 0;