gpio-f7188x: Add F81866 GPIO supports

Add F81866 GPIO supports

Fintek F81866 is a SuperIO. It contains HWMON/GPIO/Serial Ports.
and it has totally 72(9x8 sets) gpio pins.

Here is the PDF spec:
http://www.alldatasheet.com/datasheet-pdf/pdf/459085/FINTEK/F81866AD-I.html



The control method is the same with F7188x, but we should care the address
of GPIO8x.

GPIO address is below:
    GPIO0x based: 0xf0
    GPIO1x based: 0xe0
    GPIO2x based: 0xd0
    GPIO3x based: 0xc0
    GPIO4x based: 0xb0
    GPIO5x based: 0xa0
    GPIO6x based: 0x90
    GPIO7x based: 0x80
    GPIO8x based: 0x88 <-- not 0x70.

Signed-off-by: Peter Hung <hpeter+linux_kernel@gmail.com>
Acked-by: Simon Guinot <simon.guinot@sequanux.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>