MFC: r272248

  - Cleanups pc98 code.
  - Remove unworked formats.
MFC r273727:
Original commit message was
Allow the vfs.nfsd knobs to be set from loader.conf (or using
kenv(8)).  This is useful when nfsd is loaded as module.

As I understand, automatic fetch from kenv does not work in stable/10.
Merge the change still, to reduce code difference.
MFC r273728:
Add a method to iicbus to request IIC_M_NOSTOP behaviour for multibyte
transfers to be default.
MFC: r272252

  Drop the 3rd clause from all 3 clause BSD licenses.