Bring joystick icons into XDG compliance

diff --git a/kcontrol/joystick/joystick.desktop b/kcontrol/joystick/joystick.desktop
index 5b2226c..5b977af 100644
--- a/kcontrol/joystick/joystick.desktop
+++ b/kcontrol/joystick/joystick.desktop
@@ -5,7 +5,7 @@
 X-TDE-FactoryName=kcm_joystick
 X-TDE-Library=joystick
 X-TDE-Test-Module=true
-Icon=joystick
+Icon=input-joystick
 X-DocPath=kcontrol/joystick/index.html
 Categories=Qt;TDE;X-TDE-settings-hardware;
 Name=Joystick