ACPI: Kconfig: always enable CONFIG_ACPI_SLEEP on X86

The SMP dependency on HOTPLUG_CPU and SUSPEND_SMP
caused more harm than good -- making ACPI sleep
support vanish for configs missing those options.
So simply select them on the (ACPI && SMP && X86) systems
that need them.

Also, remove the prompt for ACPI_SLEEP,
virtually nobody (intentionally) enables ACPI without it.

Signed-off-by: Len Brown <len.brown@intel.com>