openvswitch: update kernel doc for struct vport

commit be4ace6e

 ("openvswitch: Move dev pointer into vport itself")

The commit above added @dev and moved @rcu to the bottom of struct
vport, but the change was not reflected in the kernel doc. So let's
update the kernel doc as well.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
Cc: Thomas Graf <tgraf@suug.ch>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>