rockchip: rng: Add a driver for random number generator(rng) device

Add a driver for the rng device found on rockchip platforms.
Support rng module of crypto v1 and crypto v2.

Signed-off-by: Lin Jinhan <troy.lin@rock-chips.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 6a8a667..44a0003 100644
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -7,3 +7,4 @@
 obj-$(CONFIG_RNG_MESON) += meson-rng.o
 obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
 obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
+obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o