firewire: convert client_list_lock to mutex

So far it is only taken in non-atomic contexts.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c
index ffde1be..2de3dd5 100644
--- a/drivers/firewire/fw-device.c
+++ b/drivers/firewire/fw-device.c
@@ -27,6 +27,7 @@
 #include <linux/idr.h>
 #include <linux/jiffies.h>
 #include <linux/string.h>
+#include <linux/mutex.h>
 #include <linux/rwsem.h>
 #include <linux/semaphore.h>
 #include <linux/spinlock.h>
@@ -1005,7 +1006,7 @@
 		device->node = fw_node_get(node);
 		device->node_id = node->node_id;
 		device->generation = card->generation;
-		spin_lock_init(&device->client_list_lock);
+		mutex_init(&device->client_list_mutex);
 		INIT_LIST_HEAD(&device->client_list);
 
 		/*