rng: rockchip_rng: Add compatible for RK3568

rng: rockchip_rng: Add compatible for RK3568

Linux commit afeccc408496 ("arm64: dts: rockchip: add DT entry for RNG
to RK356x") merged for v6.12-rc1 add a proper rng node to the SoC DT.
The compatible used differs compared to what U-Boot is currently using.

Add support for the rk3568-rng used in upstream Linux. Support for the
cryptov2-rng compatible is still kept because PX30/RK3326 and RK3308 are
still using it.

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