[coreboot] [PATCH] Adds a retry/faildown to SB600 SATA detection logic

[Dan Lykowski]

Adds a retry/faildown to SB600 SATA detection logic.

SATA port status kept returning 0x1: BAR5+po+28h
1h = Device presence detected but Phy communication not established
 
This patch adds logic to force 1.5g if the drive fails to communicate at 3.0g.

Thanks
Dan Lykowski

Signed-off-by: Dan Lykowski