NFC: Specify usage for targets found and target lost events

It is now specified that nfc_target_found() and nfc_target_lost() core
functions must not be called from an atomic context. This allow us to
serialize calls and protect the targets table using the nfc device lock
instead of a spinlock.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index f1829f6..77dae74 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -128,7 +128,7 @@
 		cb->args[1] = (long) dev;
 	}
 
-	spin_lock_bh(&dev->targets_lock);
+	device_lock(&dev->dev);
 
 	cb->seq = dev->targets_generation;
 
@@ -141,7 +141,7 @@
 		i++;
 	}
 
-	spin_unlock_bh(&dev->targets_lock);
+	device_unlock(&dev->dev);
 
 	cb->args[0] = i;