enc-amf: Version 2.2.4

Updates the plugin to work better with the AMF Runtime version 1.4.6.0, which removed some experimental properties.

enc-amf @ 47700617

-Subproject commit 94b260e76c0d69af7ff5ea8a1b47fe73f935fe70
+Subproject commit 477006177bdfe8285885dae46ec89723b7604a69