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

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

MFC r226173, r227843, r227848 and r227908:
Use DEVMETHOD_END to mark end of device methods.
Remove superfluous device methods.
Add some missing __FBSBID() macros.

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

Approved by: re (implicit)

Restructure how reset and poweroff are handled on PowerPC systems, since
the existing code was very platform specific, and broken for SMP systems
trying to reboot from KDB.

- Add a new PLATFORM_RESET() method to the platform KOBJ interface, and
migrate existing reset functions into platform modules.
- Modify the OF_reboot() routine to submit the request by hand to avoid
the IPIs involved in the regular openfirmware() routine. This fixes
reboot from KDB on SMP machines.
- Move non-KDB reset and poweroff functions on the Powermac platform
into the relevant power control drivers (cuda, pmu, smu), instead of
using them through the Open Firmware backdoor.
- Rename platform_chrp to platform_powermac since it has become
increasingly Powermac specific. When we gain support for IBM systems,
we will grow a new platform_chrp.

Remove the unneeded header <machine/intr.h>.

Get nexus(4) out of the RTC business. The interface used by nexus(4)
in Open Firmware was Apple-specific, and we have complete coverage of Apple
system controllers, so move RTC responsibilities into the system controller
drivers. This avoids interesting problems from manipulating these devices
through Open Firmware behind the backs of their drivers.

Obtained from: NetBSD
MFC after: 2 weeks

strict kobj signatures: fix adb_hb_controller_poll impl in powermac

the method return u_int, not void

Reviewed by: imp, current@
Approved by: jhb (mentor)

Use a static free packet queue instead of using malloc() to allocate new ADB packets.
This fixes some locking problems.

Fix some nasty race conditions in the VIA-CUDA driver that ended up preventing
my right mouse button and keyboard LEDs from working due to mangled
configuration packets. Fixed several other races and associated problems in the
main ADB stack that were exposed while fixing this.

Fix some possible infinite loops in the ADB code, and remove some hacks
that were inserted in desperation during bring-up. In addition, move ADB bus
enumeration and child attachment to when interrupts are available.

Add ADB support. This provides support for the external ADB bus on the PowerMac
G3 as well as the internal ADB keyboard and mice in PowerBooks and iBooks. This
also brings in Mac GPIO support, for which we should eventually have a better
interface.

Obtained from: NetBSD (CUDA and PMU drivers)