Devirginator update for GTA02

[Werner Almesberger]

I just checked in my changes for the devirginator and GTA02. This
isn't complete yet (the third stage for NOR is missing), and also
needs more testing.

I don't think there are many people who are using the devirginator
stright from SVN at the moment, but in case of trouble, please
revert to a revision before 4081.

(Sorry for the rush - got a plane to catch in a few minutes.)

- Werner

----------------------------------- Changes -----------------------------------

Various changes, mainly for GTA02. Note: needs more testing.

Add support for GTA02:

devirginator/setup.sh: pass openocd.in and u-boot.in through CPP
devirginator/setup.sh: new variables U_PLATFORM and U_BOARD containing upper
  case versions of PLATFORM and BOARD
devirginator/setup.sh: pass -D<platform> and -D<platform><board> (in upper
  case) to envedit.pl
devirginator/openocd.in: added GTA02 memory map
devirginator/openocd.in: enable backlight only if GTA01
devirginator/u-boot.in: corrected misleading comment regarding backlight status
devirginator/u-boot.in: updated NAND BBT location for GTA02
devirginator/u-boot.in: added distinct smiley handling (frame buffer address)
  for GTA01 and GTA02
devirginator/environment.in: added console, root device, and frame buffer
  (splash screen) handling for GTA02
devirginator/environment.in (bootcmd): limit kernel load size to 2MB

General improvements:

devirginator/Makefile: added "clean" target
devirginator/environment.in: added the "Factory reset" menu option, which used
  to be hard-coded in u-boot