avcodec/binkaudio: Avoid allocation for array

The array in question can not be too large (only 26 elements), so it can
simply be put on the context.

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/binkaudio.c

@@ -52,8 +52,8 @@ typedef struct BinkAudioContext {
     int overlap_len;        ///< overlap size (samples)
     int block_size;
     int num_bands;
-    unsigned int *bands;
     float root;
+    unsigned int bands[26];
     float previous[MAX_CHANNELS][BINK_BLOCK_MAX_SIZE / 16];  ///< coeffs from previous audio block
     float quant_table[96];
     AVPacket *pkt;
@@ -122,10 +122,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
         if (sample_rate_half <= ff_wma_critical_freqs[s->num_bands - 1])
             break;
 
-    s->bands = av_malloc((s->num_bands + 1) * sizeof(*s->bands));
-    if (!s->bands)
-        return AVERROR(ENOMEM);
-
     /* populate bands data */
     s->bands[0] = 2;
     for (i = 1; i < s->num_bands; i++)
@@ -273,7 +269,6 @@ static int decode_block(BinkAudioContext *s, float **out, int use_dct)
 static av_cold int decode_end(AVCodecContext *avctx)
 {
     BinkAudioContext * s = avctx->priv_data;
-    av_freep(&s->bands);
     if (CONFIG_BINKAUDIO_RDFT_DECODER && avctx->codec->id == AV_CODEC_ID_BINKAUDIO_RDFT)
         ff_rdft_end(&s->trans.rdft);
     else if (CONFIG_BINKAUDIO_DCT_DECODER)