libmach: rearrange mips2 files
 [rsc] --rw-rw-r-- M 128579 rsc sys 886 Mar 31 11:11 sys/src/libmach/mips2ureg.h
 [rsc] --rw-rw-r-- M 128579 glenda sys 4167 Mar 31 14:49 sys/src/libmach/0.c
	/n/sourcesdump/2006/0331/plan9/sys/src/libmach/0.c:1,9 - 
	/n/sourcesdump/2006/0401/plan9/sys/src/libmach/0.c:1,11
	  /*
	   * mips r4k definition
	+  *
	+  * currently no compiler - not related to 0c
	   */
	  #include <u.h>
	  #include <bio.h>
	- #include "0c/ureg.h"
	+ #include "mips2ureg.h"
	  #include <mach.h>
	  
	  #define	FPREGBYTES	4
	/n/sourcesdump/2006/0331/plan9/sys/src/libmach/0.c:109,114 - 
	/n/sourcesdump/2006/0401/plan9/sys/src/libmach/0.c:111,117
	  	0x1000,		/* page size */
	  	0xC0000000,	/* kernel base */
	  	0x40000000,	/* kernel text mask */
	+ 	0x7FFFFFFFULL,	/* user stack top */
	  	4,		/* quantization of pc */
	  	4,		/* szaddr */
	  	8,		/* szreg */