NFC: Quiet nci/data.c sparse noise about plain integer as NULL pointer

Pointers should be cleared with NULL, not 0.

Quiets a couple sparse warnings of the type:

warning: Using plain integer as NULL pointer

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c
index a0bc326..76c48c5 100644
--- a/net/nfc/nci/data.c
+++ b/net/nfc/nci/data.c
@@ -49,7 +49,7 @@
 
 	if (cb) {
 		ndev->data_exchange_cb = NULL;
-		ndev->data_exchange_cb_context = 0;
+		ndev->data_exchange_cb_context = NULL;
 
 		/* forward skb to nfc core */
 		cb(cb_context, skb, err);
@@ -200,10 +200,10 @@
 			pr_err("error adding room for accumulated rx data\n");
 
 			kfree_skb(skb);
-			skb = 0;
+			skb = NULL;
 
 			kfree_skb(ndev->rx_data_reassembly);
-			ndev->rx_data_reassembly = 0;
+			ndev->rx_data_reassembly = NULL;
 
 			err = -ENOMEM;
 			goto exit;
@@ -216,7 +216,7 @@
 
 		/* third, free old reassembly */
 		kfree_skb(ndev->rx_data_reassembly);
-		ndev->rx_data_reassembly = 0;
+		ndev->rx_data_reassembly = NULL;
 	}
 
 	if (pbf == NCI_PBF_CONT) {