staging: rtl8192e: remove set but not used variable 'payload '

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

drivers/staging/rtl8192e/rtllib_rx.c: In function rtllib_rx_InfraAdhoc:
drivers/staging/rtl8192e/rtllib_rx.c:1303:6: warning:
 variable payload set but not used [-Wunused-but-set-variable]
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190717143551.29200-1-yuehaibing@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192e/rtllib_rx.c

@@ -1300,7 +1300,6 @@ static int rtllib_rx_InfraAdhoc(struct rtllib_device *ieee, struct sk_buff *skb,
 	struct rx_ts_record *pTS = NULL;
 	u16 fc, sc, SeqNum = 0;
 	u8 type, stype, multicast = 0, unicast = 0, nr_subframes = 0, TID = 0;
-	u8 *payload;
 	u8 dst[ETH_ALEN];
 	u8 src[ETH_ALEN];
 	u8 bssid[ETH_ALEN] = {0};
@@ -1412,7 +1411,6 @@ static int rtllib_rx_InfraAdhoc(struct rtllib_device *ieee, struct sk_buff *skb,
 
 	/* Parse rx data frame (For AMSDU) */
 	/* skb: hdr + (possible reassembled) full plaintext payload */
-	payload = skb->data + hdrlen;
 	rxb = kmalloc(sizeof(struct rtllib_rxb), GFP_ATOMIC);
 	if (!rxb)
 		goto rx_dropped;