irqdomain: Add __rcu annotations to radix tree accessors

Fix various address spaces warning of sparse.

kernel/irq/irqdomain.c:1463:14: warning: incorrect type in assignment (different address spaces)
kernel/irq/irqdomain.c:1463:14:    expected void **slot
kernel/irq/irqdomain.c:1463:14:    got void [noderef] <asn:4>**
kernel/irq/irqdomain.c:1465:66: warning: incorrect type in argument 2 (different address spaces)
kernel/irq/irqdomain.c:1465:66:    expected void [noderef] <asn:4>**slot
kernel/irq/irqdomain.c:1465:66:    got void **slot

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: https://lkml.kernel.org/r/1506082841-11530-1-git-send-email-yamada.masahiro@socionext.com

kernel/irq/irqdomain.c

@@ -945,7 +945,7 @@ static int virq_debug_show(struct seq_file *m, void *private)
 	struct irq_desc *desc;
 	struct irq_domain *domain;
 	struct radix_tree_iter iter;
-	void **slot;
+	void __rcu **slot;
 	int i;
 
 	seq_printf(m, " %-16s  %-6s  %-10s  %-10s  %s\n",
@@ -1453,7 +1453,7 @@ out_free_desc:
 /* The irq_data was moved, fix the revmap to refer to the new location */
 static void irq_domain_fix_revmap(struct irq_data *d)
 {
-	void **slot;
+	void __rcu **slot;
 
 	if (d->hwirq < d->domain->revmap_size)
 		return; /* Not using radix tree. */