lavc/vaapi_hevc: add missing max_8bit_constraint_flag

This is accidentally missed while rebasing.
Signed-off-by: Linjie Fu <linjie.fu@intel.com>

libavcodec/vaapi_hevc.c

@@ -505,6 +505,7 @@ static int ptl_convert(const PTLCommon *general_ptl, H265RawProfileTierLevel *h2
     copy_field(frame_only_constraint_flag);
     copy_field(max_12bit_constraint_flag);
     copy_field(max_10bit_constraint_flag);
+    copy_field(max_8bit_constraint_flag);
     copy_field(max_422chroma_constraint_flag);
     copy_field(max_420chroma_constraint_flag);
     copy_field(max_monochrome_constraint_flag);