arm: dts: rockchip: fix dts for Radxa ROCK 4C+

ROCK Pi 4 series and ROCK 4C+ cannot share .dtsi file because 4C+ is
different board.

add rk3399-rock-pi-4-u-boot.dtsi contents and remove dependency of it.

no functional change is intended.

Fixes: 71a95e2efd30 ("arm: dts: rockchip: add Radxa ROCK 4C+")
Suggested-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
1 file changed