[SPARC64]: Fix inline assembler in init_irqwork_curcpu().

'tmp' cannot be a global register, because we are going
into the interrupt globals by writing to pstate.
Since we did not specify any particular register, gcc
could use anything, and in fact because of this I am
surprised we did not hit this bug earlier.
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/irq.c

@@ -1112,7 +1112,7 @@ void enable_prom_timer(void)
 void init_irqwork_curcpu(void)
 {
 	register struct irq_work_struct *workp asm("o2");
-	unsigned long tmp;
+	register unsigned long tmp asm("o3");
 	int cpu = hard_smp_processor_id();
 
 	memset(__irq_work + cpu, 0, sizeof(*workp));