ppp_generic: Simplify tx_dropped stats

Local variable dev = ppp->dev

Signed-off-by: Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 81e7fcc..ea8cdf8 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -991,7 +991,7 @@
 
  outf:
 	kfree_skb(skb);
-	++ppp->dev->stats.tx_dropped;
+	++dev->stats.tx_dropped;
 	return 0;
 }