frontends/va/config: Fix check for packed header config

Fixes: b4651890be ("frontends/va: Update conditional checks for code stability.")
Signed-off-by: Thong Thai <thong.thai@amd.com>
Tested-by: James Zhu <James.Zhu@amd.com>
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/4285
Reviewed-by: Leo Liu <leo.liu@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9020>

src/gallium/frontends/va/config.c

@@ -319,7 +319,8 @@ vlVaCreateConfig(VADriverContextP ctx, VAProfile profile, VAEntrypoint entrypoin
          }
       }
       if (attrib_list[i].type == VAConfigAttribEncPackedHeaders) {
-         if (attrib_list[i].value != 0) {
+         if (attrib_list[i].value > 1 ||
+             config->entrypoint != PIPE_VIDEO_ENTRYPOINT_ENCODE) {
             FREE(config);
             return VA_STATUS_ERROR_INVALID_VALUE;
          }