'RELENG_5_3_0_RELEASE'.

This commit was manufactured to restore the state of the 5.3-RELEASE image.

  subset ("compatible", "device_type", "model" and "name") of the standard
  properties in drivers for devices on Open Firmware supported busses. The
  standard properties "reg", "interrupts" und "address" are not covered by
  this interface because they are only of interest in the respective bridge
  code. There's a remaining standard property "status" which is unclear how
  to support properly but which also isn't used in FreeBSD at present.
  This ofw_bus kobj-interface allows to replace the various (ebus_get_node(),
  ofw_pci_get_node(), etc.) and partially inconsistent (central_get_type()
  vs. sbus_get_device_type(), etc.) existing IVAR ones with a common one.
  This in turn allows to simplify and remove code-duplication in drivers for
  devices that can hang off of more than one OFW supported bus.
- Convert the sparc64 Central, EBus, FHC, PCI and SBus bus drivers and the
  drivers for their children to use the ofw_bus kobj-interface. The IVAR-
  interfaces of the Central, EBus and FHC are entirely replaced by this. The
  PCI bus driver used its own kobj-interface and now also uses the ofw_bus
  one. The IVARs special to the SBus, e.g. for retrieving the burst size,
  remain.
  Beware: this causes an ABI-breakage for modules of drivers which used the
  IVAR-interfaces, i.e. esp(4), hme(4), isp(4) and uart(4), which need to be
  recompiled.
  The style-inconsistencies introduced in some of the bus drivers will be
  fixed by tmm@ in a generic clean-up of the respective drivers later (he
  requested to add the changes in the "new" style).
- Convert the powerpc MacIO bus driver and the drivers for its children to
  use the ofw_bus kobj-interface. This invloves removing the IVARs related
  to the "reg" property which were unused and a leftover from the NetBSD
  origini of the code. There's no ABI-breakage caused by this because none
  of these driver are currently built as modules.
  There are other powerpc bus drivers which can be converted to the ofw_bus
  kobj-interface, e.g. the PCI bus driver, which should be done together
  with converting powerpc to use the OFW PCI code from sparc64.
- Make the SBus and FHC front-end of zs(4) and the sparc64 eeprom(4) take
  advantage of the ofw_bus kobj-interface and simplify them a bit.

Reviewed by:	grehan, tmm
Approved by:	re (scottl)
Discussed with:	tmm
Tested with:	Sun AX1105, AXe, Ultra 2, Ultra 60; PPC cross-build on i386

future:

rename ttyopen() -> tty_open() and ttyclose() -> tty_close().

We need the ttyopen() and ttyclose() for the new generic cdevsw
functions for tty devices in order to have consistent naming.

o  Make debugging code conditional upon KDB instead of DDB.
o  Call kdb_alt_break() insteadof db_alt_break().

This eliminates the need for a local ioctl method.

Bump __FreeBSD_version accordingly.

linesw[] directly to using the ttyld...() functions

The ttyld...() functions ar inline so there is no performance hit.

the linedisc directly.