rng: rockchip_rng: Update compatible for RK3588

rng: rockchip_rng: Update compatible for RK3588

Linux commit 6ee0b9ad3995 ("arm64: dts: rockchip: Add rng node to
RK3588") merged for v6.15-rc1 add a proper rng node to the device tree.
The compatible used differs compared to what U-Boot is currently using.

Replace the old trngv1 compatible with the dts/upstream compatible in
the rng driver and remove the old rng node compatible override from SoC
u-boot.dtsi to keep rng working after the driver change.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>