x86: ivybridge: Add support for early GPIO init

When not relying on Coreboot for GPIO init the GPIOs must be set up
correctly. This is currently done statically through a rather ugly method.
As the GPIOs are figured out they can be moved to the device tree and set
up as needed rather than all at the start.

In this implementation, board files should call ich_gpio_set_gpio_map()
before the GPIO driver is used in order to provide the GPIO information.
We use the early PCI interface so that this driver can now be used before
relocation.

Signed-off-by: Simon Glass <sjg@chromium.org>