cxgbe(4):  some optimizations in freelist handling.

MFC after:	2 weeks.
MFV r269426:

Double test device size for ztest(1).

Illumos issue:
    5039 ztest should default to larger device sizes
    Author: Matthew Ahrens <mahrens@delphix.com>

MFC after:	2 weeks
MFV r269427:

In dnode_children_t, use C99's "[]" idiom for declaring the variable
sized array dnc_children at the end of the structure.

This prevents the compiler from mistakenly optimizing away accesses
beyond the array's defined size.

Illumos issue:
    5038 Remove "old-style" flexible array usage in ZFS.
    Author: Justin T. Gibbs <justing@spectralogic.com>

MFC after:	2 weeks
Handle wiring failures in vm_map_wire() with the new functions
pmap_unwire() and vm_object_unwire().

Retire vm_fault_{un,}wire(), since they are no longer used.

(See r268327 and r269134 for the motivation behind this change.)

Reviewed by:	kib
Sponsored by:	EMC / Isilon Storage Division
Add myself to calendar.freebsd and committers-src.dot

Phabric: D522
Reviewed by: jmmv
Approved by: jmmv (co-mentor)
Cleanup the ECN configuration handling and provide an SCTP socket
option for controlling ECN on future associations and get the
status on current associations.
A simialar pattern will be used for controlling SCTP extensions in
upcoming commits.
Don't assume that the framebuffer driver is using vt_fb_blank() when blanking
the screen during init.

MFC after:	1 week
Rewrite a loop in vm_map_wire() so that gcc doesn't think that the variable
"rv" is uninitialized.

Reported by:	bz
- Spelling corrections

Suggested by:	Garrett Cooper <yaneurabeya@gmail.com>
PR:		192101
cxgbe(4): Remove an unused version of t4_enable_vi.

MFC after:	2 weeks
Add missing comparisons to make list IDs in EXTENDED COPY per-initiator,
as they should be.  Wrap it into a function to not duplicate the code.

MFC after:	3 days
Fix some bugs in RECEIVE COPY STATUS data.

MFC after:	3 days
Plug EXTENDED COPY request data memory leak.

MFC after:	3 days
Fix a copy and paste error.

X-MFC with: 269436
Add support for the SCTP_PR_SUPPORTED socket option as specified in
http://tools.ietf.org/html/draft-ietf-tsvwg-sctp-prpolicies
Add also a sysctl controlling the default of the end-points.

MFC after: 1 week
Rework r269444 to work also for lists without IDs.

MFC after:	3 days
Add myself to committers-src.dot.
Better late than never :-)
Remove Giant acquisition from the mount and unmount pathes.

It could be claimed that two things were reasonable protected by
Giant.  One is vfsconf list links, which is converted to the new
dedicated sx vfsconf_sx.  Another is vfsconf.vfc_refcount, which is
now updated with atomics.

Note that vfc_refcount still has the same races now as it has under
the Giant, the unload of filesystem modules can happen while the
module is still in use.

Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Do the iwn(4) panic reinitialisation under IWN_LOCK().

I've checked each of the functions being called and there's either a
_locked version or it's supposed to be called with IWN_LOCK() held.
Make the witness lock limit an option.