MFC r256724:

Make geom_label(4) resize-aware.  This fixes a situation when "gpart resize"
would resize a partition, but label providers - e.g. /dev/gptid/XXX - would
stay the same size.

MFC r256766:

Fix build with gcc by spelling unused format string as "unused" instead of NULL.

Sponsored by:	The FreeBSD Foundation
MFC r257199, r257200, r257217:

  Remove all #include <machine/pmap.h> from arm code.  It's already
  included by vm/pmap.h, which is a prerequisite for arm/machine/pmap.h
  so there's no reason to ever include it directly.

  Remove #include <machine/frame.h> from all the arm code that doesn't
  really need it.  That would be almost everywhere it was included.  Add
  it in a couple files that really do need it and were previously getting
  it by accident via another header.

  Remove the last dregs of trapframe_t.  It turns out only arm was using
  this type, so remove it to make arm code more consistant with other
  platforms.