arm64: dts: rockchip: Enable HDMI Sound on rk3399-roc-pc

HDMI-Sound is the only available sound card on rk3399-roc-pc, enable it.

Signed-off-by: Markus Reichl <m.reichl@fivetechno.de>
Link: https://lore.kernel.org/r/c9db5599-743b-bb90-999e-5989be6556ac@fivetechno.de


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