[ARM] pxa: only register "cpld_irq" for the correct platform

Only register the "cpld_irq" sysclass for mainstone/lubbock if we're
running on one of those platforms.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/lubbock.c b/arch/arm/mach-pxa/lubbock.c
index ebb73f1..1b9290c 100644
--- a/arch/arm/mach-pxa/lubbock.c
+++ b/arch/arm/mach-pxa/lubbock.c
@@ -136,9 +136,13 @@
 
 static int __init lubbock_irq_device_init(void)
 {
-	int ret = sysdev_class_register(&lubbock_irq_sysclass);
-	if (ret == 0)
-		ret = sysdev_register(&lubbock_irq_device);
+	int ret = -ENODEV;
+
+	if (machine_is_lubbock()) {
+		ret = sysdev_class_register(&lubbock_irq_sysclass);
+		if (ret == 0)
+			ret = sysdev_register(&lubbock_irq_device);
+	}
 	return ret;
 }