avcodec/jpeglsdec: add fall-through annotations

libavcodec/jpeglsdec.c

@@ -25,6 +25,7 @@
  * JPEG-LS decoder.
  */
 
+#include "libavutil/attributes.h"
 #include "libavutil/mem.h"
 #include "avcodec.h"
 #include "codec_internal.h"
@@ -77,6 +78,7 @@ int ff_jpegls_decode_lse(MJpegDecodeContext *s)
         break;
     case 2:
         s->palette_index = 0;
+        av_fallthrough;
     case 3:
         tid= bytestream2_get_byte(&s->gB);
         wt = bytestream2_get_byte(&s->gB);