Don't create any threads before SI_SUB_INIT_IF in the LinuxKPI. Else
kthread_add() will assert it is called too soon. This fixes a startup
issue when COMPAT_LINUXKPI is in enabled the kernel configuration
file.

Reported by: Michael Butler <imb@protected-networks.net>
MFC after: 1 week
Sponsored by: Mellanox Technologies