tipc: remove dead code in tipc_net and relatives

dist_queue is no longer used since commit 37922ea4
("tipc: permit overlapping service ranges in name table")

Acked-by: Jon Maloy <jmaloy@redhat.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Hoang Huu Le <hoang.h.le@dektech.com.au>
Link: https://lore.kernel.org/r/20201028032712.31009-1-hoang.h.le@dektech.com.au


Signed-off-by: Jakub Kicinski <kuba@kernel.org>