Convert Freescale PowerPC platforms to FDT convention.

Convert Freescale PowerPC platforms to FDT convention.

The following systems are affected:

  - MPC8555CDS
  - MPC8572DS

This overhaul covers the following major changes:

  - All integrated peripherals drivers for Freescale MPC85XX SoC, which are
    currently in the FreeBSD source tree are reworked and adjusted so they
    derive config data out of the device tree blob (instead of hard coded /
    tabelarized values).

  - This includes: LBC, PCI / PCI-Express, I2C, DS1553, OpenPIC, TSEC, SEC,
    QUICC, UART, CFI.

  - Thanks to the common FDT infrastrucutre (fdtbus, simplebus) we retire
    ocpbus(4) driver, which was based on hard-coded config data.

Note that world for these platforms has to be built WITH_FDT.

Reviewed by:	imp
Sponsored by:	The FreeBSD Foundation