crypto: hisilicon/trng - add HiSilicon TRNG driver support

Move existing char/hw_random/hisi-trng-v2.c to crypto/hisilicon/trng.c.

Signed-off-by: Weili Qian <qianweili@huawei.com>
Reviewed-by: Zaibo Xu <xuzaibo@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>