erdtlsenc: Don't force typecast on callbacks
erdtlsenc: Don't force typecast on callbacks

Use the correct prototypes instead, and cast where required.

shelsonjava/openwebrtc-gst-plugins,shelsonjava/openwebrtc-gst-plugins,shelsonjava/openwebrtc-gst-plugins,shelsonjava/openwebrtc-gst-plugins