intel/gm45: new northbridge

The code supports DDR3 boards only. RAM init for DDR2 is sufficiently
different that it requires separate code, and we have no boards to
test that.

Change-Id: I9076546faf8a2033c89eb95f5eec524439ab9fe1
Signed-off-by: Patrick Georgi <patrick.georgi@secunet.com>
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/1689
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
26 files changed