kdb,ftdump: Remove reference to internal kdb include

Now that include/linux/kdb.h properly exports all the functions
required to dynamically add a kdb shell command, the reference to the
private kdb header can be removed.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

kernel/trace/trace_kdb.c

@@ -13,7 +13,6 @@
 #include <linux/kdb.h>
 #include <linux/ftrace.h>
 
-#include "../debug/kdb/kdb_private.h"
 #include "trace.h"
 #include "trace_output.h"