keyboard: advertise KT_DEAD2 extended diacriticals

In addition to KT_DEAD which has limited support for diacriticals,
there is KT_DEAD2 that can support 256 criticals, so let's advertise
it in <linux/keyboard.h>.

This lets userland know abut the drivers/char/keyboard.c function
k_dead2, which supports more than the few trivial ones that k_dead
supports.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/keyboard.h

@@ -56,6 +56,7 @@ extern int unregister_keyboard_notifier(struct notifier_block *nb);
 #define KT_ASCII	9
 #define KT_LOCK		10
 #define KT_SLOCK	12
+#define KT_DEAD2	13
 #define KT_BRL		14
 
 #define K(t,v)		(((t)<<8)|(v))