usb_enable() must be called by the application.
The application may want to register usb_dc_status_callback
and trace usb status codes (usb_dc_status_code).
Signed-off-by: Emil Obalski <emil.obalski@nordicsemi.no>
1. Remove usb_descriptor.h as tracing_backend_usb.c doesn't have access
to that include file.
2. Make TRACING_BACKEND_USB depend on USB being enabled.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Tracing subsystem is growing and although related to debugging, it does
deserve to belong into its own subsystem.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>