PR28543, readelf entered an infinite loop

This little tweak terminates fuzzed binary readelf output a little
quicker.

	PR 28543
	* dwarf.c (read_and_display_attr_value): Consume a byte when
	form is unrecognized.

binutils/dwarf.c

@@ -2743,6 +2743,8 @@ read_and_display_attr_value (unsigned long           attribute,
       
     default:
       warn (_("Unrecognized form: 0x%lx\n"), form);
+      /* What to do?  Consume a byte maybe?  */
+      ++data;
       break;
     }