arm64: dts: mt7986: add built-in Wi-Fi device nodes

This enables built-in 802.11ax Wi-Fi support.

Reviewed-by: Sam Shih <sam.shih@mediatek.com>
Reviewed-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Link: https://lore.kernel.org/r/20220901130552.26234-1-chui-hao.chiu@mediatek.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>