vm_radix_init: use initializer

[dougm]

Summary

Several vm_radix tries are not initialized with vm_radix_init. That works, for now, since static initialization zeroes the root field anyway, but if initialization changes, these tries will fail. Add missing initializer calls.

Test Plan

A kernel that checked for proper initialization was built and run on amd64 and all the vm_radix tries that were used were verified as properly initialized.

[alc]

sys/vm/vm_object.c

297

If this were an ordinary object, then this would happen before the call to _vm_object_allocate().

[dougm]

Move lines after written and verbal direction from alc.

[alc]

sys/arm64/arm64/pmap.c

1290–1299

Ugh, in reviewing this, I observed that neither arm64 nor riscv ever TAILQ_INIT() the pm_pvchunk field. I believe that the only reason that they don't crash is that their first operations on the field are TAILQ_FIRST() and TAILQ_INSERT_HEAD().