net: moxa: constify net_device_ops structures

Declare net_device_ops structure as const as it is only stored in
the netdev_ops field of a net_device structure. This field is of type
const, so net_device_ops structures having same properties can be made
const too.
Done using Coccinelle:

@r1 disable optional_qualifier@
identifier i;
position p;
@@
static struct net_device_ops i@p={...};

@ok1@
identifier r1.i;
position p;
struct net_device ndev;
@@
ndev.netdev_ops=&i@p

@bad@
position p!={r1.p,ok1.p};
identifier r1.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r1.i;
@@
+const
struct net_device_ops i;

File size before:
   text	   data	    bss	    dec	    hex	filename
   4821	    744	      0	   5565	   15bd ethernet/moxa/moxart_ether.o

File size after:
   text	   data	    bss	    dec	    hex	filename
   5373	    192	      0	   5565	   15bd ethernet/moxa/moxart_ether.o
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/moxa/moxart_ether.c

@@ -436,7 +436,7 @@ static void moxart_mac_set_rx_mode(struct net_device *ndev)
 	spin_unlock_irq(&priv->txlock);
 }
 
-static struct net_device_ops moxart_netdev_ops = {
+static const struct net_device_ops moxart_netdev_ops = {
 	.ndo_open		= moxart_mac_open,
 	.ndo_stop		= moxart_mac_stop,
 	.ndo_start_xmit		= moxart_mac_start_xmit,