x86: gpio: Correct GPIO setup ordering

x86: gpio: Correct GPIO setup ordering

The Intel GPIO driver can set up the GPIO pin mapping when the first GPIO
is probed. However, it assumes that the first GPIO to be probed is in the
first GPIO bank. If this is not the case then the init will write to the
wrong registers.

Fix this. Also add a note that this code is deprecated. We should move to
using device tree instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>