drivers/net/wireless/mwifiex/scan.c: test the just-initialized value

Test the just-initialized value rather than some other one.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
identifier x,y,f!={PTR_ERR,ERR_PTR,ERR_CAST};
statement S;
@@

x = f(...);
(
if (\(x == NULL\|IS_ERR(x)\)) S
|
*if (\(y == NULL\|IS_ERR(y)\))
 { ... when != x
   return ...; }
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/scan.c

@@ -1480,8 +1480,8 @@ mwifiex_update_curr_bss_params(struct mwifiex_private *priv,
 		return -ENOMEM;
 	}
 	beacon_ie = kzalloc(ie_len, GFP_KERNEL);
-	if (!bss_desc) {
-		dev_err(priv->adapter->dev, " failed to alloc bss_desc\n");
+	if (!beacon_ie) {
+		dev_err(priv->adapter->dev, " failed to alloc beacon_ie\n");
 		return -ENOMEM;
 	}
 	memcpy(beacon_ie, ie_buf, ie_len);