Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Toss bogus mergeinfo.

MFC r235634

Fix and update battery status bits according to linux driver

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

- Add the possibility to reuse the already last used timeout when patting
the watchdog, via the watchdog(9) interface.
For that, the WD_LASTVAL bitwise operation is used. It is mutually
exclusive with any explicit timout passing to the watchdogs.
The last timeout can be returned via the wdog_kern_last_timeout()
KPI.
- Add the possibility to pat the watchdogs installed via the watchdog(9)
interface from the kernel.
In order to do that the new KPI wdog_kern_pat() is offered and it does
accept normalized nanoseconds or WD_LASTVAL.
- Avoid to pass WD_ACTIVE down in the watchdog handlers. All the control
bit processing should over to the upper layer functions and not passed
down to the handlers at all.

These changes are intended to be used in order to fix up the watchdog
tripping in situation when the userland is busted, but protection is still
wanted (examples: shutdown syncing / disk dumping).

Sponsored by: Sandvine Incorporated
Reviewed by: emaste, des, cognet
MFC after: 2 weeks

Revisit the watchdogs: Resetting the error to EINVAL after failing to set the
watchdog might hide the succesful arming of an earlier one. Accept that on
failing to arm any watchdog (because of non-supported timeouts) EOPNOTSUPP is
returned instead of the more appropriate EINVAL.

MFC after: 3 days

Align the interfaces for the various watchdogs and make the interface
behave as expected.

Also:
- Return an error if WD_PASSIVE is passed in to the ioctl as only
WD_ACTIVE is implemented at the moment. See sys/watchdog.h for an
explanation of the difference between WD_ACTIVE and WD_PASSIVE.
- Remove the I_HAVE_TOTALLY_LOST_MY_SENSE_OF_HUMOR define. If you've
lost your sense of humor, than don't add a define.

Specific changes:

i80321_wdog.c
Don't roll your own passive watchdog tickle as this would defeat the
purpose of an active (userland) watchdog tickle.

ichwd.c / ipmi.c:
WD_ACTIVE means active patting of the watchdog by a userland process,
not whether the watchdog is active. See sys/watchdog.h.

kern_clock.c:
(software watchdog) Remove a check for WD_ACTIVE as this does not make
sense here. This reverts r1.181.

Return zero when disabling watchdog, unless any of the drivers complain.

Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.

Add a generic watchdog facility which through a single device entry
in /dev controls all available watchdog implementations.