avcodec/proresdec: Include required headers directly

Do not rely on an indirect inclusion of avcodec.h in proresdsp.h.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/proresdec.h

@@ -22,10 +22,15 @@
 #ifndef AVCODEC_PRORESDEC_H
 #define AVCODEC_PRORESDEC_H
 
+#include <stdint.h>
+
 #include "get_bits.h"
 #include "blockdsp.h"
 #include "proresdsp.h"
 
+#include "libavutil/frame.h"
+#include "libavutil/pixfmt.h"
+
 typedef struct {
     const uint8_t *data;
     unsigned mb_x;