Introduce domain_init_status to keep track of the init status of the domains
list (surprise). 0 = uninitialized, 1 = initialized/unpopulated, 2 =
initialized/done. Higher values can be used to support late addition of
domains which right now "works", but is potential dangerous. I choose to
only give a warning when doing so.
Use domain_init_status with if_attachdomain[1]() to ensure that we have a
complete domains list when we init the if_afdata array. Store the current
value of domain_init_status in if_afdata_initialized. This way we can update
if_afdata after a new protocol has been added (once that is allowed).
Submitted by: se (with changes)
Reviewed by: julian, glebius, se
PR: kern/73321 (partly)
69fb23b73d