x86: Move tsc_calibration to x86_init_ops

TSC calibration is modified by the vmware hypervisor and paravirt by
separate means. Moorestown wants to add its own calibration routine as
well. So make calibrate_tsc a proper x86_init_ops function and
override it by paravirt or by the early setup of the vmware
hypervisor.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/xen/enlighten.c

@@ -844,7 +844,6 @@ static const struct pv_init_ops xen_init_ops __initdata = {
 static const struct pv_time_ops xen_time_ops __initdata = {
 	.set_wallclock = xen_set_wallclock,
 	.get_wallclock = xen_get_wallclock,
-	.get_tsc_khz = xen_tsc_khz,
 	.sched_clock = xen_sched_clock,
 };
 
@@ -980,6 +979,8 @@ asmlinkage void __init xen_start_kernel(void)
 	x86_init.timers.setup_percpu_clockev = x86_init_noop;
 	x86_cpuinit.setup_percpu_clockev = x86_init_noop;
 
+	x86_platform.calibrate_tsc = xen_tsc_khz;
+
 #ifdef CONFIG_X86_64
 	/*
 	 * Setup percpu state.  We only need to do this for 64-bit