Bluetooth: bluecard: Comparison to NULL could be re-written

replaced 'not null' comparison that is readable, reported by checkpatch.

Signed-off-by: Prasanna Karthik <mkarthi3@visteon.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/bluecard_cs.c

@@ -390,7 +390,7 @@ static void bluecard_receive(struct bluecard_info *info,
 	for (i = 0; i < len; i++) {
 
 		/* Allocate packet */
-		if (info->rx_skb == NULL) {
+		if (!info->rx_skb) {
 			info->rx_state = RECV_WAIT_PACKET_TYPE;
 			info->rx_count = 0;
 			info->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);