6l,8l: fix gdb crash.

DWARF function types no longer need to be pointer-ified explicitly.
Fixes #1579.

R=rsc, lvd1
CC=golang-dev
https://golang.org/cl/4247065

src/cmd/ld/dwarf.c

@@ -1117,7 +1117,6 @@ defgotype(Sym *gotype)
 			fld = newdie(die, DW_ABRV_FUNCTYPEPARAM, s->name+5);
 			newrefattr(fld, DW_AT_type, defptrto(defgotype(s)));
 		}
-		die = defptrto(die);
 		break;
 
 	case KindInterface: