mach.h: add ObjSpim.
 [rsc] --rw-rw-r-- M 128579 glenda sys 8641 Mar 31 09:12 sys/include/mach.h
	/n/sourcesdump/2006/0331/plan9/sys/include/mach.h:92,97 - 
	/n/sourcesdump/2006/0401/plan9/sys/include/mach.h:92,98
	  	ObjAlpha,		/* .7 */
	  	ObjSparc64,		/* .u */
	  	ObjAmd64,		/* .6 */
	+ 	ObjSpim,		/* .0 */
	  	Maxobjtype,
	  
	  	CNONE  = 0,		/* symbol table classes */