Hide question about SERIO_LIBPS2 unless there is some remote

reason the user migth want to see it.

Under any normal use it gets auto-selected by PS/2 mouse or ATKBD
support anyway, and if those aren't selected there's no reason to
select this one either unless you have some very special uses.

drivers/input/serio/Kconfig

@@ -132,7 +132,7 @@ config SERIO_MACEPS2
 	  module will be called maceps2.
 
 config SERIO_LIBPS2
-	tristate "PS/2 driver library"
+	tristate "PS/2 driver library" if EMBEDDED
 	depends on SERIO
 	help
 	  Say Y here if you are using a driver for device connected