Use VA_FOURCC_YUY2 instead of YUYV (#92)

Mesa <= 24.3 incorrectly uses non-standard VA YUYV fourcc.

src/rocjpeg_vaapi_decoder.h

@@ -48,9 +48,6 @@ THE SOFTWARE.
 #include "rocjpeg_parser.h"
 #include "../api/rocjpeg.h"
 
-/*Note: va.h doesn't have VA_FOURCC_YUYV defined but vaExportSurfaceHandle returns 0x56595559 for packed YUYV for YUV 4:2:2*/
-#define ROCJPEG_FOURCC_YUYV 0x56595559
-
 /**
  * @brief Enumeration representing the compute partition for the MI300+ family of GPUs.
  */