toshiba_acpi: Support SPFC as an HCI method

Some Toshiba models, notably those with the TOS1900 device, use
the SPFC method for HCI calls instead of GHCI. Test for this method
if GHCI isn't found, and if it exists use it for all HCI calls.

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>