Staging: rtl8188eu: rtw_mlme: Fix uninitialized variable authmode

The variable authmode can be uninitialized. The danger would be if
it equals to _WPA_IE_ID_ (0xdd) or _WPA2_IE_ID_ (0x33). We can avoid
this by setting it to zero instead. This is the approach that was
used in the rtl8723bs driver.

Fixes: 7b464c9 ("staging: r8188eu: Add files for new driver - part 4")
Co-developed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200728072153.9202-1-dinghao.liu@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: dinghaoliu

drivers/staging/rtl8188eu/core/rtw_mlme.c

@@ -1729,9 +1729,11 @@ int rtw_restruct_sec_ie(struct adapter *adapter, u8 *in_ie, u8 *out_ie, uint in_
 	if ((ndisauthmode == Ndis802_11AuthModeWPA) ||
 	    (ndisauthmode == Ndis802_11AuthModeWPAPSK))
 		authmode = _WPA_IE_ID_;
-	if ((ndisauthmode == Ndis802_11AuthModeWPA2) ||
+	else if ((ndisauthmode == Ndis802_11AuthModeWPA2) ||
 	    (ndisauthmode == Ndis802_11AuthModeWPA2PSK))
 		authmode = _WPA2_IE_ID_;
+	else
+		authmode = 0x0;
 
 	if (check_fwstate(pmlmepriv, WIFI_UNDER_WPS)) {
 		memcpy(out_ie + ielength, psecuritypriv->wps_ie, psecuritypriv->wps_ie_len);