staging: rtl8188eu: remove unused variable from os_dep/ioctl_linux.c

Remove set but unused variable 'reason' from within the file
os_dep/ioctl_linux.c in the function rtw_wx_set_mlme, as it is
triggering a kernel test robot warning.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210615223607.13863-6-phil@philpotter.co.ukSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/os_dep/ioctl_linux.c

@@ -978,15 +978,12 @@ static int rtw_wx_set_mlme(struct net_device *dev,
 			   union iwreq_data *wrqu, char *extra)
 {
 	int ret = 0;
-	u16 reason;
 	struct adapter *padapter = netdev_priv(dev);
 	struct iw_mlme *mlme = (struct iw_mlme *)extra;
 
 	if (!mlme)
 		return -1;
 
-	reason = mlme->reason_code;
-
 	switch (mlme->cmd) {
 	case IW_MLME_DEAUTH:
 		if (!rtw_set_802_11_disassociate(padapter))