google/gru: Add SKU ID for Scarlet

Scarlet has SKU detection strapping pins now. This patch adds the code
to read them.

BUG=b:69373077

Change-Id: I8d889a845950923bc7b5be9b79792cf3c8b6b8ad
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/22697
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed