Add required va/va.h header, should fix 'make checkheaders'.

Originally committed as revision 18249 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/vaapi.h

@@ -25,6 +25,7 @@
 #define AVCODEC_VAAPI_H
 
 #include <stdint.h>
+#include <va/va.h>
 
 /**
  * \defgroup VAAPI_Decoding VA API Decoding