toshiba_acpi: Use handle for HCI calls

Now that we're using an acpi driver we already have a handle to
the namespace of the HCI call, so there's no need to test various
paths to the HCI call or even be aware of the path at all.

Signed-off-by: Azael Avalos <coproscefalo@gmail.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>