board: ge: bx50v3: check b850v3 power management watchdog

Set `bootcause' from b850v3 power management watchdog status.

Boot cause "REVERT" is no longer used, remove it.

Signed-off-by: Ian Ray <ian.ray@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2 files changed