definitions.
* Include <mips/cpuregs.h> in <cpu.h> so kern_clock.c has user/kernel
status bits in scope. Still needs work; r2k/r4k previous-mode bits
are different.
* Include <mips/mips_param.h> in pica/include/param.h, for locore declarations,
and definitions of vm and other constants that should be shared across
NetBSD/mips systems to esnsure user-level binary compatibility.