x86: fix setup of cyc2ns in tsc_64.c

When the TSC is calibrated against the PIT due to the nonavailability
of PMTIMER/HPET or due to SMI interference then the setup of the per
CPU cyc2ns variables is skipped. This is unlikely to happen but it
would definitely render sched_clock() unusable.

This was introduced with commit 53d517cdbaac704352b3d0c10fecb99e0b54572e

    x86: scale cyc_2_nsec according to CPU frequency

Update the per CPU cyc2ns variables in all exit pathes of tsc_calibrate.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org

arch/x86/kernel/tsc_64.c

@@ -227,14 +227,14 @@ void __init tsc_calibrate(void)
 	/* hpet or pmtimer available ? */
 	if (!hpet && !pm1 && !pm2) {
 		printk(KERN_INFO "TSC calibrated against PIT\n");
-		return;
+		goto out;
 	}
 
 	/* Check, whether the sampling was disturbed by an SMI */
 	if (tsc1 == ULONG_MAX || tsc2 == ULONG_MAX) {
 		printk(KERN_WARNING "TSC calibration disturbed by SMI, "
 		       "using PIT calibration result\n");
-		return;
+		goto out;
 	}
 
 	tsc2 = (tsc2 - tsc1) * 1000000L;
@@ -255,6 +255,7 @@ void __init tsc_calibrate(void)
 
 	tsc_khz = tsc2 / tsc1;
 
+out:
 	for_each_possible_cpu(cpu)
 		set_cyc2ns_scale(tsc_khz, cpu);
 }