powerpc/xive: Fix xmon support on the PowerNV platform

The PowerNV platform has multiple IRQ chips and the xmon command
dumping the state of the XIVE interrupt should only operate on the
XIVE IRQ chip.

Fixes: 5896163 ("powerpc/xmon: Improve output of XIVE interrupts")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200306150143.5551-3-clg@kaod.org

arch/powerpc/sysdev/xive/common.c

@@ -258,11 +258,15 @@ notrace void xmon_xive_do_dump(int cpu)
 
 int xmon_xive_get_irq_config(u32 hw_irq, struct irq_data *d)
 {
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
 	int rc;
 	u32 target;
 	u8 prio;
 	u32 lirq;
 
+	if (!is_xive_irq(chip))
+		return -EINVAL;
+
 	rc = xive_ops->get_irq_config(hw_irq, &target, &prio, &lirq);
 	if (rc) {
 		xmon_printf("IRQ 0x%08x : no config rc=%d\n", hw_irq, rc);