of/irq: init struct resource to 0 in of_irq_to_resource()

It almost does not matter because most users use only the ->start member
of the struct. However if this struct is passed to a platform device
which is then added via platform_device_add() then the ->parent member is
also used.

Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Signed-off-by: Grant Likely <[e-mail]>

drivers/of/irq.c

···
 	if (r && irq) {
 		const char *name = NULL;
 
+		memset(r, 0, sizeof(*r));
 		/*
 		 * Get optional "interrupts-names" property to add a name
 		 * to the resource.