output: elf,dwarf -- Fix lookup over existing files

We are missing @next access here so in result we
might allocate same name several times.

Reported-by: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

output/outelf.c

@@ -3298,6 +3298,7 @@ static void dwarf_findfile(const char * fname)
                 dwarf_clist = match;
                 return;
             }
+            match = match->next;
         }
     }