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/Kconfig b/drivers/rng/Kconfig
index edb6152..e4b22d7 100644
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -31,4 +31,12 @@
 	help
 	  Enable STM32MP1 rng driver.
 
+config RNG_ROCKCHIP
+	bool "Enable random number generator for rockchip crypto rng"
+	depends on ARCH_ROCKCHIP && DM_RNG
+	default n
+	help
+	  Enable random number generator for rockchip.This driver is
+	  support rng module of crypto v1 and crypto v2.
+
 endif