avcodec/adpcm_psx: always fetch next byte irregardless of flag

Even though all samples are meant to be zero (if flag == 0x07),
doesn't mean that they aren't there. See No$PSX docs [1].

[1]: https://problemkaputt.de/psx-spx.htm#spuadpcmsamples

Signed-off-by: Zane van Iperen <zane@zanevaniperen.com>

libavcodec/adpcm.c

@@ -2008,7 +2008,6 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
                     for (n = 0; n < 28; n++) {
                         int sample = 0, scale;
 
-                        if (flag < 0x07) {
                         if (n & 1) {
                             scale = sign_extend(byte >> 4, 4);
                         } else {
@@ -2016,6 +2015,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
                             scale = sign_extend(byte, 4);
                         }
 
+                        if (flag < 0x07) {
                             scale  = scale * (1 << 12);
                             sample = (int)((scale >> shift) + (c->status[channel].sample1 * xa_adpcm_table[filter][0] + c->status[channel].sample2 * xa_adpcm_table[filter][1]) / 64);
                         }