Broke up parse_mp_table() into 2 passes:

Broke up parse_mp_table() into 2 passes:
 - The 1st (preparse_mp_table()) counts the number of cpus, busses, etc. and
   records the LOCAL and IO APIC addresses.
 - The 2nd pass (parse_mp_table()) does the actual parsing of info and recording
   into the incore MP table.

This will allow us to defer the 2nd pass untill malloc() & private pages
are available (but thats for another day!).