NFC: The core part should generate the target index

The target index can be used by userspace to uniquely identify a target
and thus should be kept unique, per NFC adapter. Moreover, some protocols
do not provide a logical index when discovering new targets, so we have to
generate one for them.
For NCI or pn533 to fetch their logical index, we added a logical_idx field
to the target structure.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/nfc/core.c b/net/nfc/core.c
index deb4721..d924000 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -428,10 +428,15 @@
 int nfc_targets_found(struct nfc_dev *dev,
 		      struct nfc_target *targets, int n_targets)
 {
+	int i;
+
 	pr_debug("dev_name=%s n_targets=%d\n", dev_name(&dev->dev), n_targets);
 
 	dev->polling = false;
 
+	for (i = 0; i < n_targets; i++)
+		targets[i].idx = dev->target_idx++;
+
 	spin_lock_bh(&dev->targets_lock);
 
 	dev->targets_generation++;