skylake: Add I2C devices

Add the I2C devices to skylake with the scan_bus handler for SMBUS
devices so that I2C-based devices can be declared in devicetree.cb
and get initialized properly during ramstage.

This does not yet provide the I2C driver, but it allows for devices
that are declared in devicetree.cb to provide ACPI tables to the OS.

Change-Id: I9dfe4a06a8b0bc549a2b0e2d7c033c895188ba30
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/14992
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2 files changed