baytrail: Add GPIO initial configuration infrastructure.

During ramstage, call mainboard_get_gpios to get initial GPIO configuration
from the mainboard code, then initialize GPIOs as requested.

TEST=Manual. Using bayleybay GPIO table, set UART GPIOs to 'function 1',
and verify UART still works after GPIO configuration. Also, verify
legacy GPIO config is functional by toggling test pin.

Change-Id: Ic58d8ddd15c4dc48a751a83f6d26c7809c1efc42
Reviewed-by: Aaron Durbin <>
Commit-Queue: Shawn Nematbakhsh <>
Tested-by: Shawn Nematbakhsh <>
4 files changed