meta-p8 systems: Fix phosphor-gpio-monitor crash

The P8 systems use different GPIOs for checkstop, and cause
phosphor-gpio-monitor crash.
Define correct GPIO key for each P8 systems to fix the issue.

Fixes openbmc/openbmc#2349

Change-Id: I5f8dd79e17971091e799f9498959b307f03702b6
Signed-off-by: Lei YU <mine260309@gmail.com>
6 files changed