Make PIX_FMT format list arrays const.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

libavfilter/vf_lut.c

@@ -141,15 +141,15 @@ static av_cold void uninit(AVFilterContext *ctx)
     PIX_FMT_ABGR,         PIX_FMT_BGRA,         \
     PIX_FMT_RGB24,        PIX_FMT_BGR24
 
-static enum PixelFormat yuv_pix_fmts[] = { YUV_FORMATS, PIX_FMT_NONE };
-static enum PixelFormat rgb_pix_fmts[] = { RGB_FORMATS, PIX_FMT_NONE };
-static enum PixelFormat all_pix_fmts[] = { RGB_FORMATS, YUV_FORMATS, PIX_FMT_NONE };
+static const enum PixelFormat yuv_pix_fmts[] = { YUV_FORMATS, PIX_FMT_NONE };
+static const enum PixelFormat rgb_pix_fmts[] = { RGB_FORMATS, PIX_FMT_NONE };
+static const enum PixelFormat all_pix_fmts[] = { RGB_FORMATS, YUV_FORMATS, PIX_FMT_NONE };
 
 static int query_formats(AVFilterContext *ctx)
 {
     LutContext *lut = ctx->priv;
 
-    enum PixelFormat *pix_fmts = lut->is_rgb ? rgb_pix_fmts :
+    const enum PixelFormat *pix_fmts = lut->is_rgb ? rgb_pix_fmts :
                                        lut->is_yuv ? yuv_pix_fmts : all_pix_fmts;
 
     avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));