powerpc/xive: Move a dereference below a NULL test

Move the dereference of xc below the NULL test.
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/sysdev/xive/common.c

@@ -1010,12 +1010,13 @@ static void xive_ipi_eoi(struct irq_data *d)
 {
 	struct xive_cpu *xc = __this_cpu_read(xive_cpu);
 
-	DBG_VERBOSE("IPI eoi: irq=%d [0x%lx] (HW IRQ 0x%x) pending=%02x\n",
-		    d->irq, irqd_to_hwirq(d), xc->hw_ipi, xc->pending_prio);
-
 	/* Handle possible race with unplug and drop stale IPIs */
 	if (!xc)
 		return;
+
+	DBG_VERBOSE("IPI eoi: irq=%d [0x%lx] (HW IRQ 0x%x) pending=%02x\n",
+		    d->irq, irqd_to_hwirq(d), xc->hw_ipi, xc->pending_prio);
+
 	xive_do_source_eoi(xc->hw_ipi, &xc->ipi_data);
 	xive_do_queue_eoi(xc);
 }