include/spd_bin.h: Add SPD IO layer
By default, PCH SMBus codes will be called to retrieve SPD data. This
patch adds a SPD IO layer so that SoC could implement its specific SPD
IO layer functions such as using Integrated Memory Controller to get
SPD data.
Change-Id: I656298aeda409fca3c85266b5b8727fac9bfc917
Signed-off-by: Yuchi Chen <yuchi.chen@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84201
Reviewed-by: Shuo Liu <shuo.liu@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>