Fixed potential division by 0 with corrupted real file and VLC_CODEC_RA_288.

(cherry picked from commit b62d7ff5)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

modules/demux/real.c

@@ -1537,6 +1537,11 @@ static int CodecAudioParse( demux_t *p_demux, int i_tk_id, const uint8_t *p_data
         break;
 
     case VLC_FOURCC('2','8','_','8'):
+        if( i_coded_frame_size <= 0 )
+        {
+            es_format_Clean( &fmt );
+            return VLC_EGENERIC;
+        }
         fmt.i_codec = VLC_CODEC_RA_288;
         fmt.audio.i_blockalign = i_coded_frame_size;
         break;