irqdomain: Fix debugfs formatting

This patch fixes the irq_domain_mapping debugfs output to pad pointer
values with leading zeros so that pointer values are displayed
correctly.  Otherwise you get output similar to "0x 5e0000000000000".
Also, when the irq_domain is set to 'null'
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: David Daney <david.daney@cavium.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>

kernel/irq/irqdomain.c

@@ -643,8 +643,8 @@ static int virq_debug_show(struct seq_file *m, void *private)
 	void *data;
 	int i;
 
-	seq_printf(m, "%-5s  %-7s  %-15s  %-18s  %s\n", "virq", "hwirq",
-		      "chip name", "chip data", "domain name");
+	seq_printf(m, "%-5s  %-7s  %-15s  %-*s  %s\n", "irq", "hwirq",
+		      "chip name", 2 * sizeof(void *) + 2, "chip data", "domain name");
 
 	for (i = 1; i < nr_irqs; i++) {
 		desc = irq_to_desc(i);
@@ -667,7 +667,7 @@ static int virq_debug_show(struct seq_file *m, void *private)
 			seq_printf(m, "%-15s  ", p);
 
 			data = irq_desc_get_chip_data(desc);
-			seq_printf(m, "0x%16p  ", data);
+			seq_printf(m, data ? "0x%p  " : "  %p  ", data);
 
 			if (desc->irq_data.domain && desc->irq_data.domain->of_node)
 				p = desc->irq_data.domain->of_node->full_name;