Move most of the timer interrupt related PPC code to ppc_lib/interrupts.c

* Patch by Anders Larsen, 17 Sep 2003:
  Bring ARM memory layout in sync with the documentation:
  stack and malloc-heap are now located _below_ the U-Boot code

get rid of MK_CMD_ENTRY macro; update doc/README.command

(autoscript, bmp, bsp, fat, mmc, nand, portio, ...)

  - remove trailing white space, trailing empty lines, C++ comments, etc.
  - split cmd_boot.c (separate cmd_bdinfo.c and cmd_load.c)

* Patches by Kenneth Johansson, 25 Jun 2003:
  - major rework of command structure
    (work done mostly by Michal Cendrowski and Joakim Kristiansen)

* Patch by Murray Jensen, 24 Jun 2003:
  - make sure to use only U-boot provided header files
  - fix problems with ".rodata.str1.4" section as used by GCC-3.x

- hymod update
- cleanup (especially for gcc-3.x compilers)

- Hymod board database mods: add "who" field and new xilinx chip types
- provide new "init_cmd_timeout()" function so code external to
  "common/main.c" can use the "reset_cmd_timeout()" function before
  entering the main loop
- add DTT support for adm1021 (new file dtt/adm1021.c; config
  slightly different. see include/configs/hymod.h for an example
  (requires CONFIG_DTT_ADM1021, CONFIG_DTT_SENSORS, and
  CFG_DTT_ADM1021 defined)
- add new "eeprom_probe()" function which has similar args and
  behaves in a similar way to "eeprom_read()" etc.
- add 8260 FCC ethernet loopback code (new "eth_loopback_test()"
  function which is enabled by defining CONFIG_ETHER_LOOPBACK_TEST)
- gdbtools copyright update
- ensure that set_msr() executes the "sync" and "isync" instructions
  after the "mtmsr" instruction in cpu/mpc8260/interrupts.c
- 8260 I/O ports fix: Open Drain should be set last when configuring
- add SIU IRQ defines for 8260
- allow LDSCRIPT override and OBJCFLAGS initialization: change to
  config.mk to allow board configurations to override the GNU
  linker script, selected via the LDSCRIPT, make variable, and to
  give an initial value to the OBJCFLAGS make variable
- 8260 i2c enhancement:
  o correctly extends the timeout depending on the size of all
    queued messages for both transmit and receive
  o will not continue with receive if transmit times out
  o ensures that the error callback is done for all queued tx
    and rx messages
  o correctly detects both tx and rx timeouts, only delivers one to
    the callback, and does not overwrite an earlier error
  o logic in i2c_probe now correct
- add "vprintf()" function so that "panic()" function can be
  technically correct
- many Hymod board changes

  instead CFG_MONITOR_LEN is now only used to determine  _at_compile_
  _time_  (!) if the environment is embedded within the U-Boot image,
  or in a separate flash sector.

* Cleanup CFG_DER #defines in config files (wd maintained only)

  Change behaviour of NetLoop(): return -1 for errors, filesize
  otherwise; return code 0 is valid an means no file loaded - in this
  case the environment still gets updated!

* Patches by Jon Diekema, 9 Nov 2002:
  - improve ADC/DAC clocking on the SACSng board to align
    the failing edges of LRCLK and SCLK
  - sbc8260 configuration tweaks
  - add status LED support for 82xx systems
  - wire sspi/sspo commands into command handler; improved error
    handlering
  - add timestamp support and alternate memory test to the
    SACSng configuration