Composite Device Functions

acm_cdc_notify — issue CDC notification to host
acm_bind_config — add a CDC ACM function to a configuration
ecm_bind_config — add CDC Ethernet network link to a configuration
geth_bind_config — add CDC Subset network link to a configuration
obex_bind_config — add a CDC OBEX function to a configuration
gser_bind_config — add a generic serial function to a configuration

At this writing, a few of the current gadget drivers have been converted to this framework. Near-term plans include converting all of them, except for "gadgetfs".