ethernet: atheros: fix return value check in atl1c_tso_csum()

in atl1c_tso_csum, it should check the return value of pskb_trim(),
and return an error code if an unexpected value is returned
by pskb_trim().
Signed-off-by: Yuanjun Gong <ruc_gongyuanjun@163.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/atl1c/atl1c_main.c

@@ -2094,8 +2094,11 @@ static int atl1c_tso_csum(struct atl1c_adapter *adapter,
 			real_len = (((unsigned char *)ip_hdr(skb) - skb->data)
 					+ ntohs(ip_hdr(skb)->tot_len));
 
-			if (real_len < skb->len)
-				pskb_trim(skb, real_len);
+			if (real_len < skb->len) {
+				err = pskb_trim(skb, real_len);
+				if (err)
+					return err;
+			}
 
 			hdr_len = skb_tcp_all_headers(skb);
 			if (unlikely(skb->len == hdr_len)) {