r8152: Use guard clause and fix comment typos

Use a guard clause in tx_bottom() to reduce the indentation of the
do-while loop.

Also, fix a couple of spelling and grammatical mistakes in the
r8152_csum_workaround() function comment.

Change-Id: I460befde150ad92248fd85b0f189ec2df2ab8431
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Grant Grundler <grundler@chromium.org>
Acked-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/r8152.c

@@ -1688,7 +1688,7 @@ static struct tx_agg *r8152_get_tx_agg(struct r8152 *tp)
 }
 
 /* r8152_csum_workaround()
- * The hw limites the value the transport offset. When the offset is out of the
+ * The hw limits the value of the transport offset. When the offset is out of
  * range, calculate the checksum by sw.
  */
 static void r8152_csum_workaround(struct r8152 *tp, struct sk_buff *skb,
@@ -2178,6 +2178,7 @@ static void tx_bottom(struct r8152 *tp)
 	int res;
 
 	do {
+		struct net_device *netdev = tp->netdev;
 		struct tx_agg *agg;
 
 		if (skb_queue_empty(&tp->tx_queue))
@@ -2188,8 +2189,8 @@ static void tx_bottom(struct r8152 *tp)
 			break;
 
 		res = r8152_tx_agg_fill(tp, agg);
-		if (res) {
-			struct net_device *netdev = tp->netdev;
+		if (!res)
+			continue;
 
 		if (res == -ENODEV) {
 			rtl_set_unplug(tp);
@@ -2206,7 +2207,6 @@ static void tx_bottom(struct r8152 *tp)
 			list_add_tail(&agg->list, &tp->tx_free);
 			spin_unlock_irqrestore(&tp->tx_lock, flags);
 		}
-		}
 	} while (res == 0);
 }