x86: convert TSC disabling to generic cpuid disable bitmap

Fix from: Ian Campbell <ijc@hellion.org.uk>

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index d083ff5..b3721fd 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -592,7 +592,7 @@
 	set_normalized_timespec(&wall_to_monotonic,
 				-xtime.tv_sec, -xtime.tv_nsec);
 
-	tsc_disable = 0;
+	setup_force_cpu_cap(X86_FEATURE_TSC);
 
 	xen_setup_timer(cpu);
 	xen_setup_cpu_clockevents();