the same method to access TOD clock, so move chipset-dependent mcclock
routines to appropriate files.
This should also fix Express RISCserver and RISCserver2200 (aka R96) support
which has been broken since "struct platform" was introduced.
- J96A (Express5800/240 R4400 EISA) requires different method to access
todclock from other NEC machines (it's similar with magnum),
so handle it in p_nec_j96a.c.
Now my NEC Express5800/240 works. (and now I can test 53c700 SCSI.)