sh/intc: Fix potential race in installing chained IRQ handler

Fix a race where a pending interrupt could be received and the handler
called before the handler's data has been setup, by moving the call to
irq_set_chained_handler() after the function which sets up the handler
data.

Found by code inspection.
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Simon Horman <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: linux-sh@vger.kernel.org

drivers/sh/intc/virq.c

@@ -243,8 +243,9 @@ static void __init intc_subgroup_map(struct intc_desc_int *d)
 		 */
 		irq_set_nothread(irq);
 
-		irq_set_chained_handler(entry->pirq, intc_virq_handler);
+		/* Set handler data before installing the handler */
 		add_virq_to_pirq(entry->pirq, irq);
+		irq_set_chained_handler(entry->pirq, intc_virq_handler);
 
 		radix_tree_tag_clear(&d->tree, entry->enum_id,
 				     INTC_TAG_VIRQ_NEEDS_ALLOC);