powerpc: Remove i8259 irq_host_ops->unmap

It was never called because the host is always IRQ_HOST_MAP_LEGACY.

And what it purported to do was mask the interrupt (which will already
have happend if we shutdown the interrupt), then synchronise_irq and
clear the chip pointer, both of which will have been be done by the
caller were we to call unmap on a legacy irq.
Signed-off-by: NMilton Miller <miltonm@bga.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/sysdev/i8259.c

@@ -185,18 +185,6 @@ static int i8259_host_map(struct irq_host *h, unsigned int virq,
 	return 0;
 }
 
-static void i8259_host_unmap(struct irq_host *h, unsigned int virq)
-{
-	/* Make sure irq is masked in hardware */
-	i8259_mask_irq(irq_get_irq_data(virq));
-
-	/* remove chip and handler */
-	irq_set_chip_and_handler(virq, NULL, NULL);
-
-	/* Make sure it's completed */
-	synchronize_irq(virq);
-}
-
 static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
 			    const u32 *intspec, unsigned int intsize,
 			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
@@ -220,7 +208,6 @@ static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
 static struct irq_host_ops i8259_host_ops = {
 	.match = i8259_host_match,
 	.map = i8259_host_map,
-	.unmap = i8259_host_unmap,
 	.xlate = i8259_host_xlate,
 };