avcodec/dcadec: map Lw/Rw to FLC/FRC

Some 7.1 DTS files seem to signal Lw/Rw channels that the decoder has been
mapping to SL/SR, despite the macro for the mask being called 7_1_WIDE.
This resulted in said samples reporting the same native layout as actual 7.1
samples with Lsr/Rsr/Lss/Rss (mapped to BL/BR/SL/SR).

If we were to be strict, Lw/Rw would map to WR/WL, but that would result in an
unusual native layout. Instead, lets map them to FLC/FRC, which will result in
the more common 7.1(wide) native layout.

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/dcadec.c

@@ -41,7 +41,7 @@ int ff_dca_set_channel_layout(AVCodecContext *avctx, int *ch_remap, int dca_mask
 
     static const uint8_t dca2wav_wide[28] = {
          2,  0, 1, 4,  5,  3,  8,  4,  5,  9, 10, 6, 7, 12,
-        13, 14, 3, 9, 10, 11, 12, 14, 16, 15, 17, 8, 4,  5,
+        13, 14, 3, 6,  7, 11, 12, 14, 16, 15, 17, 8, 4,  5,
     };
 
     DCAContext *s = avctx->priv_data;