crypto: qcom-rng - Add ACPI support

Add support for probing on ACPI systems, with ACPI HID QCOM8160.

On ACPI systems, clocks are always enabled, the PRNG should
already be enabled, and the register region is read-only.
The driver only verifies that the hardware is already
enabled never tries to disable or configure it.

Signed-off-by: Timur Tabi <timur@codeaurora.org>
Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>
[port to crypto API]
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>