list: Remove cds_list_* wrappers

list: Remove cds_list_* wrappers

Use the cds_list_* types and macros directly instead of redefining them.
This makes it clear that we're not using the Linux kernel implementation
of list_head but the one from urcu.

Also make sure _LGPL_SOURCE is defined everywhere the urcu
functionality is used, such that we get the statically linkable version
with reduced overhead.

Reference: https://lwn.net/Articles/573424/#qq2answer
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>