Staging: rtl8188eu: rtw_mlme: Fix uninitialized variable authmode

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: 80fdee289f5e ("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>