rpmsg: char: Remove the unneeded result variable

Return the value rpmsg_chrdev_eptdev_add() directly instead of storing it
in another redundant variable.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Link: https://lore.kernel.org/r/20220826071954.252485-1-ye.xingchen@zte.com.cnSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

drivers/rpmsg/rpmsg_char.c

@@ -424,15 +424,12 @@ int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent
 			       struct rpmsg_channel_info chinfo)
 {
 	struct rpmsg_eptdev *eptdev;
-	int ret;
 
 	eptdev = rpmsg_chrdev_eptdev_alloc(rpdev, parent);
 	if (IS_ERR(eptdev))
 		return PTR_ERR(eptdev);
 
-	ret = rpmsg_chrdev_eptdev_add(eptdev, chinfo);
-
-	return ret;
+	return rpmsg_chrdev_eptdev_add(eptdev, chinfo);
 }
 EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);