mpc85xx: Add board support for the eXMeritus HWW-1U-1A devices

mpc85xx: Add board support for the eXMeritus HWW-1U-1A devices

The eXMeritus HWW-1U-1A unit is a DO-160-certified 13lb 1U chassis
with 3 independent TEMPEST zones.  Two independent P2020 computers may
be found inside each zone.  Complete hardware support is included.

High-level hardware overview:
  * DO-160 certified for passenger aircraft (noncritical)
  * TEMPEST ceritified for RED/BLACK separation
  * 3 zones per chassis, 2 computers per zone (total of 6)
  * Dual-core 1.066GHz P2020 per computer
  * One 2GB DDR2 SO-RDIMM module per computer (upgradable to 4GB)
  * Removable 80GB or 160GB Intel X18-M SSD per computer
  * Front-accessible dual-port E1000E per computer
  * Front-accessible serial console per computer
  * Front-accessible USB port per computer
  * Internal Gigabit crossover within each TEMPEST zone
  * Internal unidirectional fiber links across TEMPEST zones
  * Battery-backed DS1339 I2C RTC on each CPU.

Combined, each 13lb 1U chassis contains 12GB RAM, 12 cores @ 1.066GHz,
12 front-accessible Gigabit Ethernet ports and 960GB of solid-state
storage with a total power consumption of ~200W.

Additional notes:
  * SPD detection is only known to work with the DO-160-certified DIMMs

  * CPU reset is a little quirky due to hardware misfeature.  Proper
    support for the hardware reset mechanism has been left for a later
    patch series to address.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Cc: Andy Fleming <afleming@gmail.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>