VMI_INIT_PARTIAL Fixes

1. `*_va()` methods should return VMI_FAILURE.
2. Should be supported for live VMs that don't have paging enabled.
This now becomes a bit hard to follow, I suggest putting (init_mode & VMI_INIT_COMPLETE) into its own if statement. Then we can print another debug output saying that arch init failed so only physical access will be available when partial mode was requested.