[NETLINK]: Add properly module refcounting for kernel netlink sockets.

- Remove bogus code for compiling netlink as module
- Add module refcounting support for modules implementing a netlink
  protocol
- Add support for autoloading modules that implement a netlink protocol
  as soon as someone opens a socket for that protocol

Signed-off-by: Harald Welte <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
17 files changed