Using external watchdog for KUP4 boards in mpc8xx/cpu.c;
load_sernum_ethaddr() for KUP4 boards in lib_ppc/board.c;
various changes to KUP4 board specific files
* Fixes for SL811 USB controller:
- implement workaround for broken memory stick
- improve error handling
* Increase packet send timeout to 10 ms in cpu/mpc8xx/scc.c to better
cope with congested networks.