rpmsg: glink: Release driver_override

Upon termination of the rpmsg_device, driver_override needs to be freed
to avoid leaking the potentially assigned string.

Fixes: 42cd402b ("rpmsg: Fix kfree() of static memory on setting driver_override")
Fixes: 39e47767 ("rpmsg: Add driver_override device attribute for rpmsg_device")
Reviewed-by: Chris Lew <quic_clew@quicinc.com>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230109223931.1706429-1-quic_bjorande@quicinc.com

drivers/rpmsg/qcom_glink_native.c

@@ -1455,6 +1455,7 @@ static void qcom_glink_rpdev_release(struct device *dev)
 {
 	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
 
+	kfree(rpdev->driver_override);
 	kfree(rpdev);
 }
 
@@ -1698,6 +1699,7 @@ static void qcom_glink_device_release(struct device *dev)
 
 	/* Release qcom_glink_alloc_channel() reference */
 	kref_put(&channel->refcount, qcom_glink_channel_release);
+	kfree(rpdev->driver_override);
 	kfree(rpdev);
 }