arm64: dts: clearfog-gt-8k: add wlan_disable signal hog

There is currently no DT binding for GPIO rfkill signals. To make
mini-PCIe attached WiFi devices work, use gpio-hog to hold the
wlan_disable signal de-asserted.

Signed-off-by: Thomas Schreiber <tschreibe@gmail.com>
[baruch: add pinctrl node; rename tag]
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>