avutil/internal: Move avpriv_set_systematic_pal2 decl to imgutils_internal.h

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavutil/imgutils_internal.h

@@ -22,6 +22,10 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "pixfmt.h"
+
+int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt);
+
 int ff_image_copy_plane_uc_from_x86(uint8_t       *dst, ptrdiff_t dst_linesize,
                                     const uint8_t *src, ptrdiff_t src_linesize,
                                     ptrdiff_t bytewidth, int height);