mwifiex: correct max IE length check for WPS IE

This patch is bug fix for an invalid boundry check for WPS IE.
We should check max IE length against defined macro; instead we were
checking it against size of pointer. Fix it.
Also move IE length check before allocation of memory.
Signed-off-by: NAvinash Patil <patila@marvell.com>
Signed-off-by: NBing Zhao <bzhao@marvell.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/sta_ioctl.c

@@ -797,15 +797,16 @@ static int mwifiex_set_wps_ie(struct mwifiex_private *priv,
 			       u8 *ie_data_ptr, u16 ie_len)
 {
 	if (ie_len) {
-		priv->wps_ie = kzalloc(MWIFIEX_MAX_VSIE_LEN, GFP_KERNEL);
-		if (!priv->wps_ie)
-			return -ENOMEM;
-		if (ie_len > sizeof(priv->wps_ie)) {
+		if (ie_len > MWIFIEX_MAX_VSIE_LEN) {
 			dev_dbg(priv->adapter->dev,
 				"info: failed to copy WPS IE, too big\n");
-			kfree(priv->wps_ie);
 			return -1;
 		}
+
+		priv->wps_ie = kzalloc(MWIFIEX_MAX_VSIE_LEN, GFP_KERNEL);
+		if (!priv->wps_ie)
+			return -ENOMEM;
+
 		memcpy(priv->wps_ie, ie_data_ptr, ie_len);
 		priv->wps_ie_len = ie_len;
 		dev_dbg(priv->adapter->dev, "cmd: Set wps_ie_len=%d IE=%#x\n",