diracdec: fix full range videos

Full range video had been broken by the introduction of the < 2U check
at the following line. The bitstream format kind of implies that the full
and limited ranges use different pix_fmts but that's incorrect since we
have the avctx->color_range flag. So adjust the pixel range index to
be mapped to the same pix_fmts as limited range index.
Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

libavcodec/dirac.c

@@ -262,6 +262,9 @@ static int parse_source_parameters(AVDiracSeqHeader *dsh, GetBitContext *gb,
 
     dsh->bit_depth = luma_depth;
 
+    /* Full range 8 bts uses the same pix_fmts as limited range 8 bits */
+    dsh->pixel_range_index += dsh->pixel_range_index == 1;
+
     if (dsh->pixel_range_index < 2U)
         return AVERROR_INVALIDDATA;