Input: fix potential overflows in driver/input/keyboard

Change all sprintfs into snprintfs to make sure we won't stomp on
data adjacent to our buffers.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/keyboard/newtonkbd.c b/drivers/input/keyboard/newtonkbd.c
index d10983c..40a3f55 100644
--- a/drivers/input/keyboard/newtonkbd.c
+++ b/drivers/input/keyboard/newtonkbd.c
@@ -96,7 +96,7 @@
 
 	nkbd->serio = serio;
 	nkbd->dev = input_dev;
-	sprintf(nkbd->phys, "%s/input0", serio->phys);
+	snprintf(nkbd->phys, sizeof(nkbd->phys), "%s/input0", serio->phys);
 	memcpy(nkbd->keycode, nkbd_keycode, sizeof(nkbd->keycode));
 
 	input_dev->name = "Newton Keyboard";