kernel - Fix several IPV6 issues
* Replace old critical sections with a lock around global structures,
primarily the default route list for IPV6. This fixes numerous MP
races.
* Use rtrequest*_global() instead of rtrequest*() and remove user route
socket notification (the rtrequest*_global() code should do the
notification). This fixes several issues with the per-cpu route table
getting out of sync and triggering panics, and also appears to fix
several connectivity issues.
Reported-by: Francois Tigeot <ftigeot@wolfpond.org>