mac802154: change module description

This patch changes the module description like wireless which is IEEE
802.11 "subsystem" and not "implementation".
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

net/mac802154/main.c

@@ -182,5 +182,5 @@ void ieee802154_unregister_hw(struct ieee802154_hw *hw)
 }
 EXPORT_SYMBOL(ieee802154_unregister_hw);
 
-MODULE_DESCRIPTION("IEEE 802.15.4 implementation");
+MODULE_DESCRIPTION("IEEE 802.15.4 subsystem");
 MODULE_LICENSE("GPL v2");