MFC r253754:
Partially close race between calls of orphan() method from GEOM and close()
method from ZFS core, that reliably causes use-after-free panic if SSD vdev
detached during inititial erase.

Approved by:	re (delphij)
MFC: r249410 (partial)

Remove ctl(4) from GENERIC.

With ctl(4) being built as a module and automatically loaded by ctladm(8),
this makes CTL work out of the box.

Note that unlike the original r249410, this commit does not remove the
kern.cam.ctl.disable tunable for POLA reasons.

PR:		174671, 175694, 179112
Reviewed by:	ken (original version)
Sponsored by:	FreeBSD Foundation (original version)
Approved by:	re (hrs)
MFC 253751 and 253843:

- Relax the restriction on the member interfaces with LLAs.  Two or more
  LLAs on the member interfaces are actually harmless when the parent
  interface does not have a LLA.

- Add net.link.bridge.allow_llz_overlap.  This is a knob to allow LLAs on
  a bridge and the member interfaces at the same time.  The default is 0.

Approved by:	re (marius)
Merge remote-tracking branch 'upstream-github/stable/9' into stable/9