Add Relative function to Locator interface

This adds a Relative function to the Locator interface and uses
this to determine the host and container paths for located files
(and devices). This ensures that the root (e.g. the nvidia driver
root) is stripped from the container path.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/edits/mount.go

@@ -38,8 +38,7 @@ func (d mount) toEdits() *cdi.ContainerEdits {
 // that missing info is filled in when edits are applied by querying the Mount node.
 func (d mount) toSpec() *specs.Mount {
 	s := specs.Mount{
-		HostPath: d.Path,
-		// TODO: We need to allow the container path to be customised
+		HostPath:      d.HostPath,
 		ContainerPath: d.Path,
 		Options: []string{
 			"ro",