lavc/kbdwin: add missing stdint.h include

Fixes make checkheaders
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/kbdwin.h

@@ -19,6 +19,8 @@
 #ifndef AVCODEC_KBDWIN_H
 #define AVCODEC_KBDWIN_H
 
+#include <stdint.h>
+
 /**
  * Maximum window size for ff_kbd_window_init.
  */