mfd: lpc_ich: Enable GPIO driver for DH89xxCC

Based on the Intel Datasheet for the DH89xxCC PCH, the GPIO driver
is the same as ICH_v5_GPIO, minus the fact the DH89xxCC also has
blink support. However, blink support isn't supported by the GPIO
driver so we should use ICH_v5_GPIO. Tested and working on a Meraki
MX100-HW.

Signed-off-by: Chris Blake <chrisrblake93@gmail.com>
Co-developed-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>