Bluetooth: btmrvl: Comparison to NULL re-written

NOT NULL comparison modified to be readable, reported
by checkpatch.

Signed-off-by: Prasanna Karthik <mkarthi3@visteon.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/drivers/bluetooth/btmrvl_main.c b/drivers/bluetooth/btmrvl_main.c
index bc110f6..050ad6b 100644
--- a/drivers/bluetooth/btmrvl_main.c
+++ b/drivers/bluetooth/btmrvl_main.c
@@ -184,7 +184,7 @@
 	}
 
 	skb = bt_skb_alloc(HCI_COMMAND_HDR_SIZE + len, GFP_ATOMIC);
-	if (skb == NULL) {
+	if (!skb) {
 		BT_ERR("No free skb");
 		return -ENOMEM;
 	}