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)

Factor out the duplicated macro for the device type used in the
OFW device tree for PCI bridges and add a new one for PCI Express.
While at it, take advantage of the former for the rman(9) work-
around in jbusppm(4).

Take advantage of KOBJMETHOD_END.

Add drivers for the power management devices found on Fireplane/
Safari- and JBus-based machines. Currently the main purpose of
these drivers is debugging of the resource allocation on nexus(4)
and the register content of these devices though.