tests: net: Add unit tests for mld

MLD (Multicast Listerer Discovery) unit tests when joining
or leaving an IPv6 multicast group.

Change-Id: I7cd0f4c5f31c693d816fb5d27d3d23bb27679c35
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
5 files changed