On some newer chipset (eg: BayTrail), there is an IO base address
register on the PCH device which configures the base address of a
memory-mapped I/O controller.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>