staging: rtl8188eu: remove set but unused variable from rtw_get_sec_ie

Remove set but unused variable 'sec_idx' from the rtw_get_sec_ie
function inside core/rtw_ieee80211.c, to fix a kernel test robot warning
introduced by recent removal of erroneous debug statements.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210625183007.7065-1-phil@philpotter.co.ukSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8188eu/core/rtw_ieee80211.c

@@ -465,7 +465,7 @@ int rtw_parse_wpa2_ie(u8 *rsn_ie, int rsn_ie_len, int *group_cipher, int *pairwi
 
 void rtw_get_sec_ie(u8 *in_ie, uint in_len, u8 *rsn_ie, u16 *rsn_len, u8 *wpa_ie, u16 *wpa_len)
 {
-	u8 authmode, sec_idx;
+	u8 authmode;
 	u8 wpa_oui[4] = {0x0, 0x50, 0xf2, 0x01};
 	uint cnt;
 
@@ -473,8 +473,6 @@ void rtw_get_sec_ie(u8 *in_ie, uint in_len, u8 *rsn_ie, u16 *rsn_len, u8 *wpa_ie
 
 	cnt = _TIMESTAMP_ + _BEACON_ITERVAL_ + _CAPABILITY_;
 
-	sec_idx = 0;
-
 	while (cnt < in_len) {
 		authmode = in_ie[cnt];