rng: rockchip: Use same compatible as linux

Replace the rockchip,cryptov1-rng compatible with compatibles used in
the linux device tree for RK3288, RK3328 and RK3399 to ease sync of SoC
device tree from linux.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>