[POWERPC] Invert null match behaviour for irq_hosts

Currently if you don't specify a match callback for your irq_host it's
assumed you match everything. This is a kind of opt-out approach, and
turns out to be the exception rather than the rule.

So change the semantics to be opt-in, ie. you don't match anything unless
you provide a match callback.  This in itself isn't very useful, but will
allow us to provide a default match implementation in a subsequent patch.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/iseries/irq.c

@@ -346,8 +346,15 @@ static int iseries_irq_host_map(struct irq_host *h, unsigned int virq,
 	return 0;
 }
 
+static int iseries_irq_host_match(struct irq_host *h, struct device_node *np)
+{
+	/* Match all */
+	return 1;
+}
+
 static struct irq_host_ops iseries_irq_host_ops = {
 	.map = iseries_irq_host_map,
+	.match = iseries_irq_host_match,
 };
 
 /*