remove useless #undef

Originally committed as revision 10897 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/adpcm.c

@@ -1571,5 +1571,3 @@ ADPCM_CODEC  (CODEC_ID_ADPCM_SWF, adpcm_swf);
 ADPCM_DECODER(CODEC_ID_ADPCM_THP, adpcm_thp);
 ADPCM_DECODER(CODEC_ID_ADPCM_XA, adpcm_xa);
 ADPCM_CODEC  (CODEC_ID_ADPCM_YAMAHA, adpcm_yamaha);
-
-#undef ADPCM_CODEC

libavcodec/pcm.c

@@ -523,5 +523,3 @@ PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
 PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
 PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
 PCM_CODEC(CODEC_ID_PCM_ZORK, pcm_zork);
-
-#undef PCM_CODEC