crypto: qcom-rng - Add Qcom prng driver

This ports the Qcom prng from older hw_random driver.

No change of functionality and move from hw_random to crypto
APIs is done.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>