rpmsg: fix dma_free_coherent dev parameter

dma_alloc/free_coherent APIs requires the platform specific remoteproc
device as the device parameter. We are passing vdev->dev.parent to the
dma_free_coherent function which is the generic rproc device and it is
wrong, it has to be vdev->dev.parent->parent instead, same as when we
call dma_alloc_coherent function.
Signed-off-by: Fernando Guzman Lugo <fernando.lugo@ti.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

drivers/rpmsg/virtio_rpmsg_bus.c

@@ -1008,8 +1008,8 @@ static int rpmsg_probe(struct virtio_device *vdev)
 	return 0;
 
 free_coherent:
-	dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, bufs_va,
-					vrp->bufs_dma);
+	dma_free_coherent(vdev->dev.parent->parent, RPMSG_TOTAL_BUF_SPACE,
+					bufs_va, vrp->bufs_dma);
 vqs_del:
 	vdev->config->del_vqs(vrp->vdev);
 free_vrp:
@@ -1043,7 +1043,7 @@ static void __devexit rpmsg_remove(struct virtio_device *vdev)
 
 	vdev->config->del_vqs(vrp->vdev);
 
-	dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE,
+	dma_free_coherent(vdev->dev.parent->parent, RPMSG_TOTAL_BUF_SPACE,
 					vrp->rbufs, vrp->bufs_dma);
 
 	kfree(vrp);