isom: fix redundant redeclaration of ff_mov_read_chan().

Silence a GCC warning. A leftover of the disabled version is still
available in lavf/isom.c.

libavformat/aiffdec.c

@@ -28,6 +28,7 @@
 #include "aiff.h"
 #include "isom.h"
 #include "id3v2.h"
+#include "mov_chan.h"
 
 #define AIFF                    0
 #define AIFF_C_VERSION1         0xA2805140

libavformat/isom.h

@@ -204,7 +204,6 @@ int ff_mov_read_esds(AVFormatContext *fc, AVIOContext *pb, MOVAtom atom);
 enum AVCodecID ff_mov_get_lpcm_codec_id(int bps, int flags);
 
 int ff_mov_read_stsd_entries(MOVContext *c, AVIOContext *pb, int entries);
-int ff_mov_read_chan(AVFormatContext *s, AVIOContext *pb, AVStream *st, int64_t size);
 void ff_mov_write_chan(AVIOContext *pb, int64_t channel_layout);
 
 #endif /* AVFORMAT_ISOM_H */