Add nvidia gpu support via libnvidia-container

This adds nvidia gpu support via the libnvidia-container project and
`nvidia-container-cli`.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

cmd/ctr/commands/run/run_unix.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/cmd/ctr/commands"
+	"github.com/containerd/containerd/contrib/nvidia"
 	"github.com/containerd/containerd/oci"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
@@ -123,6 +124,9 @@ func NewContainer(ctx gocontext.Context, client *containerd.Client, context *cli
 			Path: parts[1],
 		}))
 	}
+	if context.IsSet("gpus") {
+		opts = append(opts, nvidia.WithGPUs(nvidia.WithDevices(context.Int("gpus")), nvidia.WithAllCapabilities))
+	}
 	if context.IsSet("config") {
 		var s specs.Spec
 		if err := loadSpec(context.String("config"), &s); err != nil {