gpio: vt8500: Export dedicated GPIO before multifunction pins.

The vendor does not provide numbering for gpio pins. Vendor source
exports dedicated gpio pins first, followed by multifunction pins.
As this is what end users expect, this patch changes vt8500 and wm8505
to do the same.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>