Add PS2 to the config checker
Add PS2 to the config checker

This is defined in Zephyr and is used by a board in Chrome OS too.
Add it to the exception list.

BUG=b:181323955
BRANCH=none
TEST=try CQ

Signed-off-by: Simon Glass <c00b0378376498bd9cd974c388df8854c0131d27@chromium.org>
Change-Id: I77ed52e88fd14b3c4b3b891e191b52629196c041
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3449668
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Commit-Queue: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec