Fix/improve fhe_stats sysctl output.

MFC after:	2 weeks
Implement small KPI to access LUN options instead doing it by hands.

MFC after:	2 weeks
Stop telling people to use send-pr; instead point them towards Bugzilla.

Hat:		bugmeister@
MFC after:	3 days
With the move away from GNATS, point end users to a better web page
detailing how to report bugs.

Hat:		bugmeister
MFC after:	3 days
Remove non-functional remnants of control LUN -- 18MB of RAM for nothing.
Remove send-pr, the supported interface to submit bugs is now via
https://bugs.freebsd.org/submit/

Removing send-pr also removes one more piece of non-BSD-licensed software.

Hat:		bugmeister
MFC after:	3 days
Don't check the dma map address for a static DMA mapping against NULL
to determine if the mapping is valid.

Submitted by:	jhb
patch: unsign the line length to avoid overflows.

Patch(1) uses a short int for the line length, which is usually
sufficient for regular diffs, but makes no effort to signal
when there is an overflow.

Change the line length to an unsigned short int to better use
the fact that a length is never negative.  The change is loosely
inspired on a related change in DragonFly, but we avoid spending
more memory than necessary.

While here adjust the messages to be clearer on what is happening.

MFC after:	1 week
Use vn_io_fault for the writes from core dumping code.  Recursing into
VM due to copyin(9) faulting while VFS locks are held is
deadlock-prone there in the same way as for the write(2) syscall.

Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Fix some cosmetic issues with the use of kmem_malloc() in the i386 LDT
sysarch(2) code.

Use M_ZERO instead of explicit bzero(9).  Do not check for failed
allocation when M_WAITOK is specified (which is specified always).
Use malloc(9) when allocating memory for the intermediate copy of the
user-supplied buffer.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Fix two issues:

 - Check for rc.d directory's existence before traversing
   it;
 - Don't output * when rc.d directory is empty.

PR:		conf/190665
Submitted by:	Oleg Ginzburg <olevole olevole ru> (with changes)
MFC after:	2 weeks
Add "vendor", "product" and "revision" options to control inquiry data.

MFC after:	2 weeks
One of the intentions behind r267254 was that the global variable "sgrowsiz"
would be read once and cached in a local variable so that the resource limit
check and map entry insertion would be guaranteed to use the same value.
However, the value being passed to vm_map_insert() is still from "sgrowsiz"
and not the local variable.  Correct this oversight.

Reviewed by:	kib
Respect "vendor" option in all places.

MFC after:	2 weeks
Remove custom processing for "file" option.
Format Portal Group Tag same as istgt does -- %4.4x instead of %x.

SPC-4 spec tells it should be "two or more hexadecimal digits".
RFC3720 tells it is 16-bit value.

MFC after:	2 weeks
Fix date.
mdoc: use display block in the beginning of the EXAMPLES section.
mdoc: remove superfluous paragraph macros.
mdoc: add missing width argument to Bl -tag.