gigabyte/ga-b75m-d3h: Add new Intel mainboard

This is based on LENOVO X230 port.
Board boots to linux via SATA or USB.
All USB ports are working.

Remaining Issues:

1. Native raminit sometimes fails with "timC write discovery failed"
   even without changing the ram configuration. I suggest
   altering the native raminit code so that it reboots
   if that message appears to give a chance for the
   boot process to recover.

2. VGA does not work.
   Native graphics initialization only supports LVDS and
   the VGA Option ROM still hangs when run in SeaBIOS.

Change-Id: I91a7aab96d6c5f213b097cd55fcc47d4c94b3172
Signed-off-by: Damien Zammit <damien@zamaudio.com>
Reviewed-on: http://review.coreboot.org/7341
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>