avcodec/cbs: constify decompose_unit_types

CBS doesn't change its contents in any way whatsoever internally, and most
users already set it to a const array.
Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/av1_frame_split_bsf.c

@@ -214,7 +214,7 @@ static int av1_frame_split_init(AVBSFContext *ctx)
     if (ret < 0)
         return ret;
 
-    s->cbc->decompose_unit_types    = (CodedBitstreamUnitType*)decompose_unit_types;
+    s->cbc->decompose_unit_types    = decompose_unit_types;
     s->cbc->nb_decompose_unit_types = FF_ARRAY_ELEMS(decompose_unit_types);
 
     if (!ctx->par_in->extradata_size)

libavcodec/av1_parser.c

@@ -191,7 +191,7 @@ static av_cold int av1_parser_init(AVCodecParserContext *ctx)
     if (ret < 0)
         return ret;
 
-    s->cbc->decompose_unit_types    = (CodedBitstreamUnitType *)decompose_unit_types;
+    s->cbc->decompose_unit_types    = decompose_unit_types;
     s->cbc->nb_decompose_unit_types = FF_ARRAY_ELEMS(decompose_unit_types);
 
     return 0;

libavcodec/cbs.h

@@ -196,7 +196,7 @@ typedef struct CodedBitstreamContext {
      * Types not in this list will be available in bitstream form only.
      * If NULL, all supported types will be decomposed.
      */
-    CodedBitstreamUnitType *decompose_unit_types;
+    const CodedBitstreamUnitType *decompose_unit_types;
     /**
      * Length of the decompose_unit_types array.
      */