ACPI: remove CONFIG_ACPI_POWER

Remove CONFIG_ACPI_POWER.  It was always set the same as CONFIG_ACPI,
and it had no menu label, so there was no way to set it to anything
other than "y".

The interfaces under CONFIG_ACPI_POWER (acpi_device_sleep_wake(),
acpi_power_transition(), etc) are called unconditionally from the
ACPI core, so we already depend on it always being present.

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