enums.xml: Add missing GSC board id flags

BUG=b:328827724
TEST=none

Change-Id: Iff354325b0064857b1ff98d359e68710f453f8fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5357694


Reviewed-by: Howard Yang <hcyang@google.com>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Mary Ruthven <mruthven@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1271677}