sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

usb: Remove unused devclass arguments to DRIVER_MODULE.

Refactor CTL datamove KPI.

- Make frontends call unified CTL core method ctl_datamove_done()
to report move completion. It allows to reduce code duplication
in differerent backends by accounting DMA time in common code.
- Add to ctl_datamove_done() and be_move_done() callback samethr
argument, reporting whether the callback is called in the same
context as ctl_datamove(). It allows for some cases like iSCSI
write with immediate data or camsim frontend write save one context
switch, since we know that the context is sleepable.
- Remove data_move_done() methods from struct ctl_backend_driver,
unused since forever.

MFC after: 1 month

Drop "All rights reserved" from all my stuff. This includes
Foundation copyrights, approved by emaste@. It does not include
files which carry other people's copyrights; if you're one
of those people, feel free to make similar change.

Reviewed by: emaste, imp, gbe (manpages)
Differential Revision: https://reviews.freebsd.org/D26980

usb: clean up empty lines in .c and .h files

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (2 of many)

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked). Use it in
preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Reviewed by: hselasky, kib
Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D23632

Add SPDX identifiers to linux_ptrace.c and cfumass.c.

MFC after: 2 weeks

Implement use of multiple transfers per I/O.

This change removes limitation of single S/G list entry and limitation on
maximal I/O size, using multiple data transfers per I/O if needed. Also
it removes code duplication between send and receive paths, which are now
completely equal.

Use ctl_queue_sense() to implement sense data reporting.

USB MS BBB transport does not support autosense, so we have to queue any
sense data back to CTL for later fetching via REQUEST SENSE.

Update kern_data_resid according to r312291.

This now mandatory for correct operation.

Add USB Mass Storage CTL frontend. This makes it possible
for USB OTG-capable hardware to implement device side of USB
Mass Storage, ie pretend it's a flash drive. It's configured
in the same way as other CTL frontends, using ctladm(8)
or ctld(8). Differently from usfs(4), all the configuration
can be done without rebuilding the kernel.

Testing and review is welcome. Right now I'm still moving,
and I don't have access to my test environment, so I'm somewhat
reluctant to making larger changes to this code; on the other
hand I don't want to let it sit on Phab until my testing setup
is back, because I want to get it into 11.1-RELEASE.

Reviewed by: emaste (cursory), wblock (man page)
MFC after: 2 weeks
Relnotes: yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D8787