dctref: make sure function declarations match between .c and .h file

libavcodec/dctref.h

@@ -22,10 +22,8 @@
 #ifndef AVCODEC_DCTREF_H
 #define AVCODEC_DCTREF_H
 
-#include "dsputil.h"
-
-void ff_ref_fdct(DCTELEM *block);
-void ff_ref_idct(DCTELEM *block);
+void ff_ref_fdct(short *block);
+void ff_ref_idct(short *block);
 void ff_ref_dct_init(void);
 
 #endif /* AVCODEC_DCTREF_H */