Input: keyboard handler - use printk_ratelimit()

Use printk_ratelimit() to protect ourselves from buggy drivers or
devices endlessly generating invalid events.

Suggested by Andrew Morton.
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

drivers/char/keyboard.c

@@ -1135,7 +1135,7 @@ static void kbd_keycode(unsigned int keycode, int down, int hw_raw)
 
 	if ((raw_mode = (kbd->kbdmode == VC_RAW)) && !hw_raw)
 		if (emulate_raw(vc, keycode, !down << 7))
-			if (keycode < BTN_MISC)
+			if (keycode < BTN_MISC && printk_ratelimit())
 				printk(KERN_WARNING "keyboard.c: can't emulate rawmode for keycode %d\n", keycode);
 
 #ifdef CONFIG_MAGIC_SYSRQ	       /* Handle the SysRq Hack */