ACPI: delete CPU_IDLE=n code

CPU_IDLE=y has been default for ACPI=y since Nov-2007,
and has shipped in many distributions since then.

Here we delete the CPU_IDLE=n ACPI idle code, since
nobody should be using it, and we don't want to
maintain two versions.
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/Kconfig

@@ -9,6 +9,7 @@ menuconfig ACPI
 	depends on PCI
 	depends on PM
 	select PNP
+	select CPU_IDLE
 	default y
 	---help---
 	  Advanced Configuration and Power Interface (ACPI) support for