[NETROM]: Implement G8PZT Circuit reset for NET/ROM

NET/ROM is lacking a connection reset like TCP's RST flag which at times
may result in a connecting having to slowly timing out instead of just being
reset.  An earlier attempt to reset the connection by sending a
NR_CONNACK | NR_CHOKE_FLAG transport was inacceptable as it did result in
crashes of BPQ systems.  An alternative approach of introducing a new
transport type 7 (NR_RESET) has be implemented several years ago in
Paula Jayne Dowie G8PZT's Xrouter.

Implement NR_RESET for Linux's NET/ROM but like any messing with the state
engine consider this experimental for now and thus control it by a sysctl
(net.netrom.reset) which for the time being defaults to off.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 532a6c5..3a29a9f 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -544,7 +544,8 @@
 	NET_NETROM_TRANSPORT_REQUESTED_WINDOW_SIZE=8,
 	NET_NETROM_TRANSPORT_NO_ACTIVITY_TIMEOUT=9,
 	NET_NETROM_ROUTING_CONTROL=10,
-	NET_NETROM_LINK_FAILS_COUNT=11
+	NET_NETROM_LINK_FAILS_COUNT=11,
+	NET_NETROM_RESET=12
 };
 
 /* /proc/sys/net/ax25 */