usb: gadget: add tracepoints to the gadget API

This new set of tracepoints will help all gadget
drivers and UDC drivers when problem appears. Note
that, in order to be able to add tracepoints to
udc-core.c we had to rename that to core.c and
statically link it with trace.c to form
udc-core.o. This is to make sure that module name
stays the same.

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

include/linux/usb/gadget.h

@@ -25,6 +25,8 @@
 #include <linux/workqueue.h>
 #include <linux/usb/ch9.h>
 
+#define UDC_TRACE_STR_MAX	512
+
 struct usb_ep;
 
 /**
@@ -324,6 +326,7 @@ struct usb_gadget_ops {
  * @dev: Driver model state for this abstract device.
  * @out_epnum: last used out ep number
  * @in_epnum: last used in ep number
+ * @mA: last set mA value
  * @otg_caps: OTG capabilities of this gadget.
  * @sg_supported: true if we can handle scatter-gather
  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
@@ -380,6 +383,7 @@ struct usb_gadget {
 	struct device			dev;
 	unsigned			out_epnum;
 	unsigned			in_epnum;
+	unsigned			mA;
 	struct usb_otg_caps		*otg_caps;
 
 	unsigned			sg_supported:1;