ck_queue: add CK_*_FOREACH_FROM

This is a variant of CK_*_FOREACH from FreeBSD queue.h which starts
iteration at the specified item. If the item pointer is NULL, iteration
starts from the beginning of the list.

Upstream commit 74366be35a6f4635f248a3c62d2d23245a4eb0f4.

MFC after: 2 weeks
Sponsored by: Klara, Inc.