arm64: dts: rockchip: add ir-receiver for rk3399-roc-pc

Like some other RK3399 boards RK3399-ROC-PC has an ir receiver
connected to pwm3 which can be used as gpio-ir-receiver.

Signed-off-by: Alex Bee <knaerzche@gmail.com>
Link: https://lore.kernel.org/r/20210619121642.7892-1-knaerzche@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>