fftools/ffplay_renderer: declare function argument as const

Declaring the function argument as const fixes a warning down the line
that the const parameter is stripped. We don't modify this argument.

Signed-off-by: Leo Izen <leo.izen@gmail.com>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>

fftools/ffplay_renderer.c

@@ -133,7 +133,7 @@ static const char *optional_device_exts[] = {
     "VK_MESA_video_decode_av1",
 };
 
-static inline int enable_debug(AVDictionary *opt)
+static inline int enable_debug(const AVDictionary *opt)
 {
     AVDictionaryEntry *entry = av_dict_get(opt, "debug", NULL, 0);
     int debug = entry && strtol(entry->value, NULL, 10);