x86: Don't show an error when the MRC cache is up to date

x86: Don't show an error when the MRC cache is up to date

When the final MRC cache record is the same as the one we want to write, we
skip writing since there is no point. This is normal behaviour.

Avoiding printing an error when this happens.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>