MFC r248857:
 - Update hardware notes to reflect that amd64 is no longer "young"
 - Bump copyright year
Merge 248070.

Fix long-standing issue with interface routes being unprotected:
Use RTM_PINNED flag to mark route as immutable.
Forbid deleting immutable routes without special rtrequest1_fib() flag.
Adding interface address with prefix already in route table is handled
by atomically deleting old prefix and adding interface one.
Remove (harmless) duplicate entry for VersionAddendum.

Noticed by:	dim@
MFC after:	1 week
MFC r248854:

  Reverse the order of some implicit commands (FS mounts and ifconfigs)
  when stopping jails.  This matters particularly for nested filesystem
  mounts.

PR:		kern/177325
Submitted by:	Harald Schmalzbauer
MFC r246293: zfs: fix, improve and re-organize page_lookup and page_unlock
MFC r248640: fbt_typoff_init: fix an off by one in determining required
memory size
MFC r248642: fbt_getargdesc: correctly handle types for return probes
MFC r248697:
  When we are removing a specific set, call ipfw_expire_dyn_rules only once.
MFC r248802:

Similar to r239870 and r239872, teach the other binutils tools about the
DW_FORM_flag_present dwarf attribute, so they do not print errors or
warnings on files that contain it.  (This attribute can be emitted by
newer versions of clang and gcc.)
MFH (r246358): load pfsync.ko if necessary.
MFH (r247270, r247271): allow starting rtadvd without any interfaces.
MFH (r247810): correctly parse mixed quoted / unquoted text.
MFH (r247285): always bootstrap liby along with yacc.
MFC r248562:
Move the vn_start_write() call in the dounmount() before setting the
MNTK_UNMOUNT flag.
MFC r248563:
Increment the write ref counter for the buffer object before calling
bundirty().
MFC r248968:
Record the correct error in the trace.
MFC r248967:
Strip the unnneeded spaces, mostly at the end of lines.
MFC r248567:
Do not call vnode_pager_setsize() while a NFS node mutex is
locked. vnode_pager_setsize() might sleep waiting for the page after
EOF be unbusied.

Call vnode_pager_setsize() both for the regular and directory vnodes.

MFC r248581:
Initialize the variable to avoid (false) compiler warning about
use of an uninitialized local.
MFC r248815:
Release the v_writecount reference on the vnode in case of error,
before the vnode is vput() in vm_mmap_vnode().
MFC r247832:
Import the likely() compat macro.

MFC r247838:
Correct the r247832.