usb: Remove usb_dc_ep_set_callback return code

Make usb_dc_ep_set_callback() return void since the code is never
used.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>

drivers/usb/device/usb_dc_dw.c

@@ -1223,11 +1223,9 @@ int usb_dc_ep_set_callback(const u8_t ep, const usb_dc_ep_callback cb)
 	return 0;
 }
 
-int usb_dc_set_status_callback(const usb_dc_status_callback cb)
+void usb_dc_set_status_callback(const usb_dc_status_callback cb)
 {
 	usb_dw_ctrl.status_cb = cb;
-
-	return 0;
 }
 
 int usb_dc_ep_mps(const u8_t ep)

drivers/usb/device/usb_dc_kinetis.c

@@ -831,12 +831,11 @@ int usb_dc_ep_set_callback(const u8_t ep, const usb_dc_ep_callback cb)
 	return 0;
 }
 
-int usb_dc_set_status_callback(const usb_dc_status_callback cb)
+void usb_dc_set_status_callback(const usb_dc_status_callback cb)
 {
-	dev_data.status_cb = cb;
 	LOG_DBG("");
 
-	return 0;
+	dev_data.status_cb = cb;
 }
 
 int usb_dc_ep_mps(const u8_t ep)

drivers/usb/device/usb_dc_native_posix.c

@@ -473,11 +473,9 @@ int usb_dc_ep_set_callback(const u8_t ep, const usb_dc_ep_callback cb)
 	return 0;
 }
 
-int usb_dc_set_status_callback(const usb_dc_status_callback cb)
+void usb_dc_set_status_callback(const usb_dc_status_callback cb)
 {
 	usbip_ctrl.status_cb = cb;
-
-	return 0;
 }
 
 int usb_dc_ep_mps(const u8_t ep)

drivers/usb/device/usb_dc_nrfx.c

@@ -1826,10 +1826,9 @@ int usb_dc_ep_set_callback(const u8_t ep, const usb_dc_ep_callback cb)
 	return 0;
 }
 
-int usb_dc_set_status_callback(const usb_dc_status_callback cb)
+void usb_dc_set_status_callback(const usb_dc_status_callback cb)
 {
 	get_usbd_ctx()->status_cb = cb;
-	return 0;
 }
 
 int usb_dc_ep_mps(const u8_t ep)

drivers/usb/device/usb_dc_sam.c

@@ -372,12 +372,11 @@ int usb_dc_set_address(u8_t addr)
 }
 
 /* Set USB device controller status callback */
-int usb_dc_set_status_callback(const usb_dc_status_callback cb)
+void usb_dc_set_status_callback(const usb_dc_status_callback cb)
 {
-	dev_data.status_cb = cb;
 	LOG_DBG("");
 
-	return 0;
+	dev_data.status_cb = cb;
 }
 
 /* Check endpoint capabilities */

drivers/usb/device/usb_dc_sam0.c

@@ -251,13 +251,11 @@ int usb_dc_set_address(const u8_t addr)
 	return 0;
 }
 
-int usb_dc_set_status_callback(const usb_dc_status_callback cb)
+void usb_dc_set_status_callback(const usb_dc_status_callback cb)
 {
 	struct usb_sam0_data *data = usb_sam0_get_data();
 
 	data->cb = cb;
-
-	return 0;
 }
 
 int usb_dc_ep_check_cap(const struct usb_dc_ep_cfg_data * const cfg)

drivers/usb/device/usb_dc_stm32.c

@@ -480,13 +480,11 @@ int usb_dc_ep_set_callback(const u8_t ep, const usb_dc_ep_callback cb)
 	return 0;
 }
 
-int usb_dc_set_status_callback(const usb_dc_status_callback cb)
+void usb_dc_set_status_callback(const usb_dc_status_callback cb)
 {
 	LOG_DBG("");
 
 	usb_dc_stm32_state.status_cb = cb;
-
-	return 0;
 }
 
 int usb_dc_set_address(const u8_t addr)

include/drivers/usb/usb_dc.h

@@ -173,10 +173,8 @@ int usb_dc_set_address(const u8_t addr);
  * The status code are described by the usb_dc_status_code enumeration.
  *
  * @param[in] cb Callback function
- *
- * @return 0 on success, negative errno code on fail.
  */
-int usb_dc_set_status_callback(const usb_dc_status_callback cb);
+void usb_dc_set_status_callback(const usb_dc_status_callback cb);
 
 /**
  * @brief check endpoint capabilities

subsys/usb/usb_device.c

@@ -1051,10 +1051,7 @@ int usb_enable(struct usb_cfg_data *config)
 	}
 
 	usb_register_status_callback(forward_status_cb);
-	ret = usb_dc_set_status_callback(forward_status_cb);
-	if (ret < 0) {
-		return ret;
-	}
+	usb_dc_set_status_callback(forward_status_cb);
 
 	ret = usb_dc_attach();
 	if (ret < 0) {
@@ -1577,10 +1574,7 @@ static int usb_composite_init(struct device *dev)
 	usb_register_custom_req_handler(custom_handler);
 
 	usb_register_status_callback(forward_status_cb);
-	ret = usb_dc_set_status_callback(forward_status_cb);
-	if (ret < 0) {
-		return ret;
-	}
+	usb_dc_set_status_callback(forward_status_cb);
 
 	/* Enable VBUS if needed */
 	ret = usb_vbus_set(true);