Support for siemens sitemp_g1p1 mainboard

[Josef Kellermann]

Added support for the Siemens 'sitemp_g1p1' mainboard.
The board is similar to the AMD dbm690t. I adapt the code from dbm690t 
according to customer requirement specification.
I have been testing Linux as well as Windows XP booting on this board.

Signed-off-by: Josef Kellermann