core/command/memory_spd: remove memory serial number field

BUG=chromium:1080668
TEST="mosys memory spd print all" on grunt

Change-Id: I4fb8779035e79b6c3f9d9cc383e2844caedc5e03
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/mosys/+/2271961
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Tested-by: Victor Ding <victording@chromium.org>
Auto-Submit: Victor Ding <victording@chromium.org>
Commit-Queue: Victor Ding <victording@chromium.org>
1 file changed