dlist: Introduce CONTAINER macros

While iterating on each node element it is much more common to try to
access the container struct which up until now have been done manually
using CONTAINER_OF macro, so this introduce CONTAINER variants that allow
to iterate directly with container pointer rather than the list node.

Change-Id: Ie1e0da948cb9517c3c5cd8e86b59b95d7d027bfa
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>