NFC: Fix next target_idx type and rename for clarity

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/rawsock.c b/net/nfc/rawsock.c
index b2825aa..ec1134c 100644
--- a/net/nfc/rawsock.c
+++ b/net/nfc/rawsock.c
@@ -92,8 +92,8 @@
 		goto error;
 	}
 
-	if (addr->target_idx > dev->target_idx - 1 ||
-	    addr->target_idx < dev->target_idx - dev->n_targets) {
+	if (addr->target_idx > dev->target_next_idx - 1 ||
+	    addr->target_idx < dev->target_next_idx - dev->n_targets) {
 		rc = -EINVAL;
 		goto error;
 	}