* commit isapnpvar.h changes required for ARC to support plain isa.
* fixup mistake over mips/include/cpuregs.h.
* mips/mips_machdep.c:
set L2 cache-size for arc, cleanup use of L2cache present
vs L2 cache-size variables. check for no L2 cache on kernels
configured to require one. misc cleanups.
* mips/mpis/trap.c: more locore stack-traceback label cleanup.
XXX Locore callbacks for mips3, mips4, r4600 cacheflush need more work.