staging: rtl8723bs: Remove set but not used variable 'i'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/staging/rtl8723bs/core/rtw_xmit.c: In function update_attrib:
drivers/staging/rtl8723bs/core/rtw_xmit.c:680:7: warning: variable i set but not used [-Wunused-but-set-variable]

It is not used since commit 554c0a3a ("staging:
Add rtl8723bs sdio wifi driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1570578905-95675-1-git-send-email-zhengbin13@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/core/rtw_xmit.c

@@ -675,7 +675,6 @@ static void set_qos(struct pkt_file *ppktfile, struct pkt_attrib *pattrib)
 
 static s32 update_attrib(struct adapter *padapter, _pkt *pkt, struct pkt_attrib *pattrib)
 {
-	uint i;
 	struct pkt_file pktfile;
 	struct sta_info *psta = NULL;
 	struct ethhdr etherhdr;
@@ -689,7 +688,7 @@ static s32 update_attrib(struct adapter *padapter, _pkt *pkt, struct pkt_attrib
 	DBG_COUNTER(padapter->tx_logs.core_tx_upd_attrib);
 
 	_rtw_open_pktfile(pkt, &pktfile);
-	i = _rtw_pktfile_read(&pktfile, (u8 *)&etherhdr, ETH_HLEN);
+	_rtw_pktfile_read(&pktfile, (u8 *)&etherhdr, ETH_HLEN);
 
 	pattrib->ether_type = ntohs(etherhdr.h_proto);