x86_64: remove pit synchronization

The APIC timer setup code synchronizes the local APIC timer to the
PIT/HPET. This is pointless as the PIT and the local APIC timer
frequency are not correlated and the APIC timer calibration can never
be accurate enough to avoid that the local APIC timer and the PIT/HPET
drift apart.

Simply remove it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>

arch/x86/kernel/apic_64.c

@@ -790,24 +790,6 @@ static void setup_APIC_timer(unsigned int clocks)
 
 	local_irq_save(flags);
 
-	/* wait for irq slice */
-	if (hpet_address && hpet_use_timer) {
-		u32 trigger = hpet_readl(HPET_T0_CMP);
-		while (hpet_readl(HPET_T0_CMP) == trigger)
-			/* do nothing */ ;
-	} else {
-		int c1, c2;
-		outb_p(0x00, 0x43);
-		c2 = inb_p(0x40);
-		c2 |= inb_p(0x40) << 8;
-		do {
-			c1 = c2;
-			outb_p(0x00, 0x43);
-			c2 = inb_p(0x40);
-			c2 |= inb_p(0x40) << 8;
-		} while (c2 - c1 < 300);
-	}
-
 	irqen = ! cpu_isset(smp_processor_id(),
 			    timer_interrupt_broadcast_ipi_mask);
 	__setup_APIC_LVTT(clocks, 0, irqen);