cpuidle: dubious one-bit signed bitfield in cpuidle.h

fix these sparse warnings:

  CHECK   arch/x86/kernel/acpi/cstate.c
include/linux/cpuidle.h:82:17: error: dubious one-bit signed bitfield
  CHECK   arch/x86/kernel/acpi/processor.c
include/linux/cpuidle.h:82:17: error: dubious one-bit signed bitfield
  CHECK   arch/x86/kernel/cpu/cpufreq/powernow-k7.c
include/linux/cpuidle.h:82:17: error: dubious one-bit signed bitfield
  CHECK   arch/x86/kernel/cpu/cpufreq/powernow-k8.c
include/linux/cpuidle.h:82:17: error: dubious one-bit signed bitfield
  CHECK   arch/x86/kernel/cpu/cpufreq/longhaul.c
include/linux/cpuidle.h:82:17: error: dubious one-bit signed bitfield
  CHECK   arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
include/linux/cpuidle.h:82:17: error: dubious one-bit signed bitfield

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>