usb: gadget: uvc: configfs: Drop leaked references to config items

Some of the .allow_link() and .drop_link() operations implementations
call config_group_find_item() and then leak the reference to the
returned item. Fix this by dropping those references where needed.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

drivers/usb/gadget/function/uvc_configfs.c

@@ -529,6 +529,7 @@ static int uvcg_control_class_allow_link(struct config_item *src,
 unlock:
 	mutex_unlock(&opts->lock);
 out:
+	config_item_put(header);
 	mutex_unlock(su_mutex);
 	return ret;
 }
@@ -564,6 +565,7 @@ static void uvcg_control_class_drop_link(struct config_item *src,
 unlock:
 	mutex_unlock(&opts->lock);
 out:
+	config_item_put(header);
 	mutex_unlock(su_mutex);
 }
 
@@ -2026,6 +2028,7 @@ static int uvcg_streaming_class_allow_link(struct config_item *src,
 unlock:
 	mutex_unlock(&opts->lock);
 out:
+	config_item_put(header);
 	mutex_unlock(su_mutex);
 	return ret;
 }
@@ -2066,6 +2069,7 @@ static void uvcg_streaming_class_drop_link(struct config_item *src,
 unlock:
 	mutex_unlock(&opts->lock);
 out:
+	config_item_put(header);
 	mutex_unlock(su_mutex);
 }