Add string support to nvramtool.

Add string support to nvramtool.

To add a string to your cmos.layout, you need to specify type 's':

#start     len       type    unused   name
416        512       s       0        boot_devices

With this patch you can do

$ nvramtool -w boot_devices="(hd0,0);(hd2,1);(hd3)"

And FILO will attempt to load a menu.lst from any of these devices in that
order.

The patch is not exactly pretty, but a cleaner solution might have resulted in
a complete rewrite of the tool, which I did not want.

Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Joseph Smith <joe@settoplinux.org>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@3613 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1