usb: cdns3: gadget: Replace trace_printk by dev_dbg

trace_printk should not be used in production code, replace it
call with dev_dbg.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>

Link: https://lore.kernel.org/r/20200627070307.516803-2-drinkcat@chromium.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>