kconfig: nuke LKC_DIRECT_LINK cruft

This interface is not (and has never been ?) used by any frontend, just get rid
of it.

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>

scripts/kconfig/zconf.l

@@ -14,7 +14,6 @@
 #include <string.h>
 #include <unistd.h>
 
-#define LKC_DIRECT_LINK
 #include "lkc.h"
 
 #define START_STRSIZE	16