hwrng: xgene - add support for APM X-Gene SoC RNG support

This adds the APM X-Gene SoC RNG support.

Signed-off-by: Feng Kan <fkan@apm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --cc drivers/char/hw_random/Kconfig
Simple merge

diff --cc drivers/char/hw_random/Makefile
Simple merge

diff --cc drivers/char/hw_random/xgene-rng.c
Simple merge