KVM/x86: Remove superfluous SMP function call

Since the following commit:

  1cf4f629d9d2 ("cpu/hotplug: Move online calls to hotplugged cpu")

... the CPU_ONLINE and CPU_DOWN_PREPARE notifiers are always run on the hot
plugged CPU, and as of commit:

  3b9d6da67e11 ("cpu/hotplug: Fix rollback during error-out in __cpu_disable()")

the CPU_DOWN_FAILED notifier also runs on the hot plugged CPU.  This patch
converts the SMP functional calls into direct calls.

smp_function_call_single() executes the function with interrupts
disabled. This calling convention is not preserved because there
is no reason to do so.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153335.452527104@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kvm/x86.c

@@ -5662,15 +5662,13 @@ static struct notifier_block kvmclock_cpufreq_notifier_block = {
 static int kvmclock_cpu_notifier(struct notifier_block *nfb,
 					unsigned long action, void *hcpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
-
 	switch (action) {
 		case CPU_ONLINE:
 		case CPU_DOWN_FAILED:
-			smp_call_function_single(cpu, tsc_khz_changed, NULL, 1);
+			tsc_khz_changed(NULL);
 			break;
 		case CPU_DOWN_PREPARE:
-			smp_call_function_single(cpu, tsc_bad, NULL, 1);
+			tsc_bad(NULL);
 			break;
 	}
 	return NOTIFY_OK;