hwrng: ingenic - Add hardware TRNG for Ingenic X1830

Add X1830 SoC digital true random number generator driver.

Tested-by: 周正 (Zhou Zheng) <sernia.zhou@foxmail.com>
Co-developed-by: 漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>
Signed-off-by: 漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>
Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>