tipc: Remove internal linked list of node objects

Eliminates a sorted list TIPC uses to keep track of the neighboring
nodes it has links to, since this duplicates information already present
in the internal array of node object pointers.

Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>