usb: gadget: use config_ep_by_speed() instead of ep_choose()

Remove obsolete functions:
1. ep_choose()
2. usb_find_endpoint()

Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/gadget/f_loopback.c b/drivers/usb/gadget/f_loopback.c
index 34e3cca..3756326 100644
--- a/drivers/usb/gadget/f_loopback.c
+++ b/drivers/usb/gadget/f_loopback.c
@@ -256,8 +256,9 @@
 
 	/* one endpoint writes data back IN to the host */
 	ep = loop->in_ep;
-	ep->desc = ep_choose(cdev->gadget,
-			&hs_loop_source_desc, &fs_loop_source_desc);
+	result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
+	if (result)
+		return result;
 	result = usb_ep_enable(ep);
 	if (result < 0)
 		return result;
@@ -265,8 +266,10 @@
 
 	/* one endpoint just reads OUT packets */
 	ep = loop->out_ep;
-	ep->desc = ep_choose(cdev->gadget,
-			&hs_loop_sink_desc, &fs_loop_sink_desc);
+	result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
+	if (result)
+		goto fail0;
+
 	result = usb_ep_enable(ep);
 	if (result < 0) {
 fail0: