xen/smp: Remove unnecessary call to smp_processor_id()

There is an extra and unnecessary call to smp_processor_id()
in cpu_bringup(). Remove it.
Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/smp.c

@@ -59,7 +59,7 @@ static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
 
 static void __cpuinit cpu_bringup(void)
 {
-	int cpu = smp_processor_id();
+	int cpu;
 
 	cpu_init();
 	touch_softlockup_watchdog();