Add "." entry as expected by dev.c.
 [rsc] --rw-rw-r-- M 733409 presotto sys 6291 Oct  2 08:10 sys/src/9/pc/devlm78.c
	/n/sourcesdump/2005/1002/plan9/sys/src/9/pc/devlm78.c:57,62 - 
	/n/sourcesdump/2005/1003/plan9/sys/src/9/pc/devlm78.c:57,63
	  };
	  
	  static Dirtab lm78dir[] = {
	+ 	".",			{ Qdir, 0, QTDIR},	0,	0555,
	  	"lm78vram",	{ Qlm78vram, 0 },	0,	0444,
	  };