[coreboot] Patches for ACPI support on dbm690t (RS600 and SB600)

[Bao, Zheng]

Hi,
Attachment are the patches for Chipset AMD RS690, AMD SB600 and mainboard DBM690T. The following ACPI features are supported.
1. S1, S5 sleep and wake up (by power button or PS/2 keyboard/mouse).
2. AMD powernow-k8 driver.
3. Thermal configuration based on ADT7461.
4. IDE timing settings.
5. HPET timer.
6. Interrupt routing based on ACPI table.

Signed-off-by:  Joe Bao 
Reviewed-by:    Maggie Li