avcodec/gsm_parser: Replace codec_id check by assert

A parser should never be called with a mismatching codec
Found-by: Ganesh Ajjanagadde <gajjanag@mit.edu>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/gsm_parser.c

@@ -25,6 +25,7 @@
  * Splits packets into individual blocks.
  */
 
+#include "libavutil/avassert.h"
 #include "parser.h"
 #include "gsm.h"
 
@@ -55,10 +56,7 @@ static int gsm_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
             s->duration   = GSM_FRAME_SIZE * 2;
             break;
         default:
-            *poutbuf      = buf;
-            *poutbuf_size = buf_size;
-            av_log(avctx, AV_LOG_ERROR, "Invalid codec_id\n");
-            return buf_size;
+            av_assert0(0);
         }
     }