staging: irda: remove the irda network stack and drivers

No one has publicly stepped up to maintain this broken codebase for
devices that no one uses anymore, so let's just drop the whole thing.

If someone really wants/needs it, we can revert this and they can fix
the code up to work properly.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>