Patch merged into coreboot/master: f943901 mc146818rtc: disable RTC before writing to nvram

the following patch was just integrated into master:
commit f943901777990554e3f5fb27b63613f6cd95c958
Author: Patrick Georgi 
Date:   Thu Nov 15 14:54:05 2012 +0100

mc146818rtc: disable RTC before writing to nvram

In principle this isn't necessary. However there's a byte (or several)
    outside the first 14 bytes that are part of the RTC, and require
    locking (century/altCentury).

Since their location is mostly unknown, guard writes properly.

Change-Id: I847cd4efa92722e8504d29feaf7dbfa5c5244b4e
    Signed-off-by: Patrick Georgi 
    Reviewed-on: http://review.coreboot.org/1868
    Tested-by: build bot (Jenkins)
    Reviewed-by: Stefan Reinauer

See http://review.coreboot.org/1868 for details.

-gerrit