Also document the maximum nuber of lanes for the different platforms. Change-Id: I52356d4bbb407ee8a36fce18ad94d73f39c01345 Signed-off-by: Felix Held <felix-coreboot@felixheld.de> Reviewed-on: https://review.coreboot.org/c/coreboot/+/44069 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>