rust: clist: Add basic list infrastructure and head iterator

Add foundational types for working with C's doubly circular linked
lists (list_head). Provide low-level iteration over list nodes.

Typed iteration over actual items will be added in a follow-up
commit using the FromListHead trait and ClistLink mechanism.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
2 files changed