powerpc/cell: Drop unused iic_get_irq_host()

Sparse checking revealed that it is no longer used. The last usage was
removed in commit 2e194583 ("[POWERPC] Cell interrupt rework") in
2006.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/cell/interrupt.c

@@ -187,12 +187,6 @@ void iic_message_pass(int cpu, int msg)
 	out_be64(&per_cpu(cpu_iic, cpu).regs->generate, (0xf - msg) << 4);
 }
 
-struct irq_domain *iic_get_irq_host(int node)
-{
-	return iic_host;
-}
-EXPORT_SYMBOL_GPL(iic_get_irq_host);
-
 static void iic_request_ipi(int msg)
 {
 	int virq;