update for CrayL1 board
* Patch by Pantelis Antoniou, 21 Apr 2003:
add boot support for ARTOS (a proprietary OS)
* Patch by Steven Scholz, 11 Apr 2003:
Add support for RTC DS1338
* Patch by Rod Boyce, 24 Jan 2003:
Fix counting of extended partitions in diskboot command
wdenk