bd82x6x: Use CMOS variable if available for power-on on power failure

We used a hard coded value for some reason. Don't do that, but use CMOS
instead.

Modelled after http://review.coreboot.org/#/c/443 to get bd82x6x in
sync.

Change-Id: I36d715310157b9f9074f2a1c80710f85833020b4
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/1324
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
1 file changed