bluetooth: Do not set IFF_POINTOPOINT

The IPv6 stack needs to send and receive Neighbor Discovery
messages. Remove the IFF_POINTOPOINT flag.

Signed-off-by: Patrik Flykt <patrik.flykt@linux.intel.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Reviewed-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>