arm64: defconfig: Enable Qualcomm pseudo rng

Most Qualcomm platforms contain a pseudo random number generator
hardware block. Enable the driver for this block and also enable the
interface for exposing this to userspace.

Tested-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>