ACPI: EC: remove .stop() method

This patch folds the .stop() method into .remove().

acpi_ec_stop() is only called via acpi_device_probe() and
acpi_device_remove(), and in both cases it is called immediately before
acpi_ec_remove(), so there's no need to have it be a separate method.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Reviewed-by: Alex Chiang <achiang@hp.com>
CC: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>