Mount nvidia.icd file needed by OpenCL

This change ensures the NVIDIA ICD file needed by
OpenCL ICD loaders gets injected into containers.
The NVIDIA ICD file tells the OpenCL runtime where
to find NVIDIA's OpenCL implementation.

fixes: https://github.com/NVIDIA/nvidia-container-toolkit/issues/682

Signed-off-by: Christopher Desiniotis <cdesiniotis@nvidia.com>