mwifiex: remove an unneeded NULL check

We dereference adapter in the error handling code so this needed to
be fixed.  This function is always called like:
	adapter->if_ops.host_to_card(adapter, ...);
so adapter can never be NULL and I've removed the NULL check.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/pcie.c

@@ -1671,9 +1671,8 @@ static int mwifiex_pcie_host_to_card(struct mwifiex_adapter *adapter, u8 type,
 				     struct sk_buff *skb,
 				     struct mwifiex_tx_param *tx_param)
 {
-	if (!adapter || !skb) {
-		dev_err(adapter->dev, "Invalid parameter in %s <%p, %p>\n",
-				__func__, adapter, skb);
+	if (!skb) {
+		dev_err(adapter->dev, "Passed NULL skb to %s\n", __func__);
 		return -1;
 	}