x86/cpufeature: Fix build bug caused by merge artifact with the removal of cpu_has_hypervisor

The 0-day build robot by Fengguang Wu reported a build failure:

   arch/x86/events//intel/cstate.c: In function 'cstate_pmu_init':
   arch/x86/events//intel/cstate.c:680:6: error: 'cpu_has_hypervisor' undeclared (first use in this function)

... which was caused by a merge mistake I made when applying
the following patch:

  0c9f3536 ("x86/cpufeature: Remove cpu_has_hypervisor")

apply the missing hunk as well.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Cc: David Kershner <david.kershner@unisys.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: sparmaintainer@unisys.com
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/1459266123-21878-3-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/events/intel/cstate.c

@@ -677,7 +677,7 @@ static int __init cstate_pmu_init(void)
 {
 	int err;
 
-	if (cpu_has_hypervisor)
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return -ENODEV;
 
 	err = cstate_init();