[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/kernel/irq.c

@@ -523,7 +523,7 @@ struct irq_host *irq_find_host(struct device_node *node)
 	 */
 	spin_lock_irqsave(&irq_big_lock, flags);
 	list_for_each_entry(h, &irq_hosts, link)
-		if (h->ops->match == NULL || h->ops->match(h, node)) {
+		if (h->ops->match != NULL && h->ops->match(h, node)) {
 			found = h;
 			break;
 		}

arch/powerpc/platforms/celleb/interrupt.c

@@ -175,11 +175,18 @@ static int beatic_pic_host_xlate(struct irq_host *h, struct device_node *ct,
 	return 0;
 }
 
+static int beatic_pic_host_match(struct irq_host *h, struct device_node *np)
+{
+	/* Match all */
+	return 1;
+}
+
 static struct irq_host_ops beatic_pic_host_ops = {
 	.map = beatic_pic_host_map,
 	.remap = beatic_pic_host_remap,
 	.unmap = beatic_pic_host_unmap,
 	.xlate = beatic_pic_host_xlate,
+	.match = beatic_pic_host_match,
 };
 
 /*

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,
 };
 
 /*

arch/powerpc/platforms/ps3/interrupt.c

@@ -673,9 +673,16 @@ static int ps3_host_map(struct irq_host *h, unsigned int virq,
 	return 0;
 }
 
+static int ps3_host_match(struct irq_host *h, struct device_node *np)
+{
+	/* Match all */
+	return 1;
+}
+
 static struct irq_host_ops ps3_host_ops = {
 	.map = ps3_host_map,
 	.unmap = ps3_host_unmap,
+	.match = ps3_host_match,
 };
 
 void __init ps3_register_ipi_debug_brk(unsigned int cpu, unsigned int virq)