crypto: qcom-rng - Add hw_random interface support

Add hw_random interface support in qcom-rng driver as new IP block
in Qualcomm SoC has inbuilt NIST SP800 90B compliant entropic source
to generate true random number.

Keeping current rng_alg interface as well for random number generation
using Kernel Crypto API.

Signed-off-by: Om Prakash Singh <quic_omprsing@quicinc.com>
Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Om Prakash Singh <quic_omprsing@quicinc.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>