pinctrl: vt8500: Ensure value reg is updated when setting direction

Current code only touches the direction register when setting direction
to output, which breaks logic like

echo high > /sys/class/gpio/gpio0/direction

which is expected to also set the value. This patch also adds a call
to update the value register when setting direction to output.

Signed-off-by: Alexey Charkov <alchark@gmail.com>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>