Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Ensure controller or namespace node name is specified before trying to
access it.

While here, also fix the identify usage message to show the -v and -x
parameters.

Sponsored by: Intel
MFC after: 3 days

Send per-namespace logpage commands to the controller devnode, so they
are processed as admin commands, not I/O commands.

As part of this change, pull out the code for parsing a namespace node
string into a separate function, since it is used for both identify and
logpage commands.

Sponsored by: Intel
MFC after: 3 days

Add firmware replacement and activation support to nvmecontrol(8) through
a new firmware command.

NVMe controllers may support up to 7 firmware slots for storing of
different firmware revisions. This new firmware command supports
firmware replacement (i.e. firmware download) with or without immediate
activation, or activation of a previously stored firmware image. It
also supports selection of the firmware slot during replacement
operations, using IDENTIFY information from the controller to
check that the specified slot is valid.

Newly activated firmware does not take effect until the new controller
reset, either via a reboot or separate 'nvmecontrol reset' command to the
same controller.

Submitted by: Joe Golio <joseph.golio@emc.com>
Obtained from: EMC / Isilon Storage Division
MFC after: 3 days

Add log page support to nvmecontrol(8) through a new logpage command.

This includes pretty printers for all of the standard NVMe log pages
(Error, SMART/Health, Firmware), as well as hex output for non-standard
or vendor-specific log pages.

Submitted by: Joe Golio <joseph.golio@emc.com>
Obtained from: EMC / Isilon Storage Division
MFC after: 3 days

Add generalized helper functions for printing hex data as part of
nvmecontrol commands.

Submitted by: Joe Golio <joseph.golio@emc.com>
Obtained from: EMC / Isilon Storage Division
MFC after: 3 days

Create #defines for NVME_CTRLR_PREFIX and NVME_NS_PREFIX for the "nvme"
and "ns" strings, rather than hardcoding the string values throughout the
nvmecontrol code base.

Sponsored by: Intel
MFC after: 3 days

Add an nvme_function structure array, defining the name, C function and
usage message for each nvmecontrol command. This helps reduce some code
clutter both now and for future commits which will add logpage and
firmware support to nvmecontrol(8).

Also move helper function prototypes to the end of the header file, after
the per-command functions.

Sponsored by: Intel
MFC after: 3 days

Break out code related to the reset command into a separate source file.

Sponsored by: Intel
MFC after: 3 days

Break out code related to the perftest command into a separate file.

Sponsored by: Intel
MFC after: 3 days

Break out code related to the identify command into a separate source file.

Sponsored by: Intel
MFC after: 3 days

Break out code related to the devlist command into a separate source file.

Sponsored by: Intel
MFC after: 3 days