can: make struct proto const

can_ioctl is the only reason for struct proto to be non-const.
script/check-patch.pl suggests struct proto be const.

Setting the reference to the common can_ioctl() in all CAN protocols directly
removes the need to make the struct proto writable in af_can.c

Signed-off-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/can/raw.c b/net/can/raw.c
index 883e9d7..649acfa 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -742,7 +742,7 @@
 	return size;
 }
 
-static struct proto_ops raw_ops __read_mostly = {
+static const struct proto_ops raw_ops = {
 	.family        = PF_CAN,
 	.release       = raw_release,
 	.bind          = raw_bind,
@@ -751,7 +751,7 @@
 	.accept        = sock_no_accept,
 	.getname       = raw_getname,
 	.poll          = datagram_poll,
-	.ioctl         = NULL,		/* use can_ioctl() from af_can.c */
+	.ioctl         = can_ioctl,	/* use can_ioctl() from af_can.c */
 	.listen        = sock_no_listen,
 	.shutdown      = sock_no_shutdown,
 	.setsockopt    = raw_setsockopt,