Change the lower bound for guest vmspace allocation to 0 instead of
using the VM_MIN_ADDRESS constant.

HardenedBSD redefines VM_MIN_ADDRESS to be 64K, which results in
bhyve VM startup failing. Guest memory is always assumed to start
at 0 so use the absolute value instead.

Reported by:	Shawn Webb, lattera at gmail com
Reviewed by:	neel, grehan
Obtained from:	Oliver Pinter via HardenedBSD
https://github.com/HardenedBSD/hardenedBSD/commit/23bd719ce1e3a8cc42fc8317b1c7c6d9e74dcba0
MFC after:	1 week
Workaround help2man defficiency that prevents mandoc from rendering
Ta is only allowed with Bl -column not in Bl -item
Fix rendering with mandoc
Fix rendering with mandoc
Fix the negation (!) operator so that it binds only to the word that
immediately follows it, which means 'not' has to be reset every time an
option word or device name is processed.
Add ARMV6 as an arm option.  This will cause obscure magic in config(8)
to automatically set the armv6 option when MACHINE_ARCH is armv6.  That
allows replacing ever-growing lists of cpu names as options to compile
a given file with the using either "optional armv6" or "optional !armv6".
Fix rendering with mandoc
Read cs_outstanding_ctl_pdus before incrementing it for NEXUS RESET task.

This removes extra log noise on idle connection termination.

MFC after:	1 week
The arm PJ4B cpu is armv7 architecture, not v6.

If this feels like deja vu... the last time this was fixed in this file
only ARM_MMU_V6 was fixed, this time it's ARM_ARCH_V6 (and this time I
searched for other occurrances of pj4b in here).