fm10k: use a local variable for the frag pointer

In the function fm10k_xmit_frame_ring, we recently switched to using
the skb_frag_size accessor instead of directly using the size member of
the skb fragment.

This made the for loop slightly harder to read because it created a very
long line that is difficult to split up. Avoid this by using a local
variable in the for loop, so that we do not have to break the line on an
open parenthesis.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/fm10k/fm10k_main.c

@@ -1073,9 +1073,11 @@ netdev_tx_t fm10k_xmit_frame_ring(struct sk_buff *skb,
 	 *       + 2 desc gap to keep tail from touching head
 	 * otherwise try next time
 	 */
-	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
-		count += TXD_USE_COUNT(skb_frag_size(
-						&skb_shinfo(skb)->frags[f]));
+	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) {
+		skb_frag_t *frag = &skb_shinfo(skb)->frags[f];
+
+		count += TXD_USE_COUNT(skb_frag_size(frag));
+	}
 
 	if (fm10k_maybe_stop_tx(tx_ring, count + 3)) {
 		tx_ring->tx_stats.tx_busy++;