arm64: dts: rockchip: add stdout path on Qnap-TS433

arm64: dts: rockchip: add stdout path on Qnap-TS433

As most Rockchip boards do, the TS433 also uses uart2 for its serial
output. Set the correct chosen entry for it.

Tested-by: Uwe Kleine-König <ukleinek@debian.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20240723195538.1133436-6-heiko@sntech.de
[ upstream commit: e1cb5d8a92e41171bf4d5ddc459bd96372500901 ]

(cherry picked from commit 1e1af2af2192490a3d174624ac1bb976aa6afffa)
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>