firewire: fix hang after card ejection

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index 0d08bf9..b72a5c1 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -1001,7 +1001,7 @@
 
 	event = reg_read(ohci, OHCI1394_IntEventClear);
 
-	if (!event)
+	if (!event || !~event)
 		return IRQ_NONE;
 
 	reg_write(ohci, OHCI1394_IntEventClear, event);