ANDROID: usb: gadget: u_ether: fix dev->trans_start removal fallout

Upstream commit 9b36627acecd (net: remove dev->trans_start), removed
dev->trans_start usage in favor of netif_trans_update(). Hence fix the
Android RNDIS multi packet support.

Fixes: AOSP Change-ID: I21c39482718944bb1b1068bdd02f626531e58f08
       ("RNDIS: Add Data aggregation (multi packet) support")
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c
index b06ede4..cb1ecfa 100644
--- a/drivers/usb/gadget/function/u_ether.c
+++ b/drivers/usb/gadget/function/u_ether.c
@@ -545,7 +545,7 @@
 					spin_lock(&dev->req_lock);
 					dev->no_tx_req_used++;
 					spin_unlock(&dev->req_lock);
-					net->trans_start = jiffies;
+					netif_trans_update(net);
 				}
 			} else {
 				spin_lock(&dev->req_lock);