google/kahlee: Add SPD function

Add the mainboard_spd_read function in romstage and call the variants
function. Grunt is the baseboard and has soldered down memory, so add
it for the default weak SPD functions and build the SPDs in cbfs.
Kahlee overrides the weak SPD function and falls back to the soc
I2C SPD functions.

BUG=b:67845441
TEST=Build and boot Kahlee.

Change-Id: I789002bfadc1a2b24f9046708986d29c0e2daf33
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/22486
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
11 files changed