net: remove unnecessary return's

One of my pet coding style peeves is the practice of
adding extra return; at the end of function.
Kill several instances of this in network code.

I suppose some coccinelle wizardy could do this automatically.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp_output.c

@@ -2071,7 +2071,6 @@ rearm_timer:
 	if (likely(!err))
 		NET_INC_STATS_BH(sock_net(sk),
 				 LINUX_MIB_TCPLOSSPROBES);
-	return;
 }
 
 /* Push out any pending frames which were held back due to