usb: dwc3: trace: purge dwc3_trace()

Finally get rid of dwc3_trace() hack. If any other
message is truly needed, we should add proper
tracepoints for them instead of hacking around with
dwc3_trace() or similar.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/Makefile

@@ -6,7 +6,7 @@ obj-$(CONFIG_USB_DWC3)			+= dwc3.o
 dwc3-y					:= core.o
 
 ifneq ($(CONFIG_FTRACE),)
-	dwc3-y				+= debug.o trace.o
+	dwc3-y				+= trace.o
 endif
 
 ifneq ($(filter y,$(CONFIG_USB_DWC3_HOST) $(CONFIG_USB_DWC3_DUAL_ROLE)),)