channels: Fix for Doxygen.

channels/chan_console.c

channels/chan_dahdi.c

channels/chan_iax2.c

channels/chan_motif.c

channels/chan_pjsip.c

channels/chan_sip.c

channels/dahdi/bridge_native_dahdi.c

channels/iax2/codec_pref.c

channels/iax2/include/firmware.h

channels/sig_analog.c

channels/sip/config_parser.c

channels/sip/include/reqresp_parser.h

channels/sip/include/route.h

channels/sip/include/sip.h

channels/sip/reqresp_parser.c