usb: gadget: f_hid: eliminate abuse of ep->driver data

Since ep->driver_data is not used for endpoint claiming, neither for
enabled/disabled state storing, we can reduce number of places where
we read or modify it's value, as now it has no particular meaning for
function or framework logic.

In case of f_hid we only need to store in ep->driver_data pointer to
struct f_hidg, as it's used in f_hidg_req_complete() callback. All
other uses of ep->driver_data are now meaningless and can be safely
removed.
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_hid.c

@@ -492,10 +492,7 @@ static void hidg_disable(struct usb_function *f)
 	struct f_hidg_req_list *list, *next;
 
 	usb_ep_disable(hidg->in_ep);
-	hidg->in_ep->driver_data = NULL;
-
 	usb_ep_disable(hidg->out_ep);
-	hidg->out_ep->driver_data = NULL;
 
 	list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
 		list_del(&list->list);
@@ -513,7 +510,6 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 
 	if (hidg->in_ep != NULL) {
 		/* restart endpoint */
-		if (hidg->in_ep->driver_data != NULL)
 		usb_ep_disable(hidg->in_ep);
 
 		status = config_ep_by_speed(f->config->cdev->gadget, f,
@@ -533,7 +529,6 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 
 	if (hidg->out_ep != NULL) {
 		/* restart endpoint */
-		if (hidg->out_ep->driver_data != NULL)
 		usb_ep_disable(hidg->out_ep);
 
 		status = config_ep_by_speed(f->config->cdev->gadget, f,
@@ -566,7 +561,6 @@ static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 						hidg->out_ep->name, status);
 			} else {
 				usb_ep_disable(hidg->out_ep);
-				hidg->out_ep->driver_data = NULL;
 				status = -ENOMEM;
 				goto fail;
 			}
@@ -614,13 +608,11 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
 	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
 	if (!ep)
 		goto fail;
-	ep->driver_data = c->cdev;	/* claim */
 	hidg->in_ep = ep;
 
 	ep = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);
 	if (!ep)
 		goto fail;
-	ep->driver_data = c->cdev;	/* claim */
 	hidg->out_ep = ep;
 
 	/* preallocate request and buffer */