[NET]: Add const markers to various variables.

the patch below marks various variables const in net/; the goal is to
move them to the .rodata section so that they can't false-share
cachelines with things that get written to, as well as potentially
helping gcc a bit with optimisations.  (these were found using a gcc
patch to warn about such variables)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 5e6bc4b..ef98b14 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1413,7 +1413,7 @@
  *	closed.
  */
 
-static unsigned char new_state[16] = {
+static const unsigned char new_state[16] = {
   /* current state:        new state:      action:	*/
   /* (Invalid)		*/ TCP_CLOSE,
   /* TCP_ESTABLISHED	*/ TCP_FIN_WAIT1 | TCP_ACTION_FIN,