drm/amdkfd: CRIU Implement KFD restore ioctl

This implements the KFD CRIU Restore ioctl that lays the basic
foundation for the CRIU restore operation. It provides support to
create the buffer objects corresponding to the checkpointed image.
This ioctl creates various types of buffer objects such as VRAM,
MMIO, Doorbell, GTT based on the date sent from the userspace plugin.
The data mostly contains the previously checkpointed KFD images from
some KFD processs.

While restoring a criu process, attach old IDR values to newly
created BOs. This also adds the minimal gpu mapping support for a single
gpu checkpoint restore use case.

Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: David Yat Sin <david.yatsin@amd.com>
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>