ACPI: remove unused acpi_device_ops .lock and .scan methods

No drivers use the .lock and .scan methods, and the Linux/ACPI
code doesn't even provide a way to invoke them, so remove them.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>