arm64: dts: mt7622: add SoC and peripheral related device nodes

Add watchdog, rtc, auxadc, cir, efuse, rng, uart[1-4], pwm, i2c[0-2],
spi[0-1], btif and thermal related nodes.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Cc: Andrew-CT Chen <andrew-ct.chen@mediatek.com>
Cc: Zhiyong Tao <zhiyong.tao@mediatek.com>
Cc: Zhi Mao <zhi.mao@mediatek.com>
Cc: Jun Gao <jun.gao@mediatek.com>
Cc: Leilk Liu <leilk.liu@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>