nvram: Add option to reset NVRAM to default parameters on every boot

In specific configurations, such as homogeneous supercomputing systems,
changeable NVRAM parameters are more of a liability than a useful tool.
This patch allows a coreboot image to be compiled that will always set
the NVRAM parameters to their default values, reducing maintainance
overhead on large clusters.

Change-Id: Ic03e34211d4a58cd60740f2d9a6b50e11fe85822
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/8446
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/drivers/pc80/mc146818rtc.c

@@ -56,6 +56,9 @@ static void cmos_reset_date(void)
 
 static int cmos_checksum_valid(int range_start, int range_end, int cks_loc)
 {
+	if (IS_ENABLED(CONFIG_STATIC_OPTION_TABLE))
+		return 1;
+
 	int i;
 	u16 sum, old_sum;
 	sum = 0;