Accept empty packed headers attribute in vaCreateConfig()

This indicates to the driver that the user will not supply any packed
headers, even though the possibility is available.  This was an API/ABI
break in cccf2a3, and existing programs
such as libavcodec do use this pattern.

Signed-off-by: Mark Thompson <[email protected]>

Author: fhvwy

src/i965_drv_video.c

@@ -1431,7 +1431,7 @@ i965_CreateConfig(VADriverContextP ctx,
         if (attrib_found) {
             uint32_t enc_packed_attribs = i965_get_enc_packed_attributes(ctx, profile, entrypoint);
 
-            if (!(attrib_found->value & enc_packed_attribs))
+            if (attrib_found->value && !(attrib_found->value & enc_packed_attribs))
                 vaStatus = VA_STATUS_ERROR_INVALID_VALUE;
         }
     }