rng: nuvoton: Add NPCM7xx rng driver

Add Nuvoton BMC NPCM750 rng driver.

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 435b3b9..0ae0ed4 100644
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -7,6 +7,7 @@
 obj-$(CONFIG_RNG_MESON) += meson-rng.o
 obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
 obj-$(CONFIG_RNG_MSM) += msm_rng.o
+obj-$(CONFIG_RNG_NPCM) += npcm_rng.o
 obj-$(CONFIG_RNG_OPTEE) += optee_rng.o
 obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
 obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o