remoteproc: Fix and restore the parenting hierarchy for vdev

The commit 086d087 ("remoteproc: create vdev subdevice with specific
dma memory pool") has introduced a new vdev subdevice for each vdev
declared in the firmware resource table and made it as the parent for the
created virtio rpmsg devices instead of the previous remoteproc device.
This changed the overall parenting hierarchy for the rpmsg devices, which
were children of virtio devices, and does not allow the corresponding
rpmsg drivers to retrieve the parent rproc device through the
rproc_get_by_child() API.

Fix this by restoring the remoteproc device as the parent. The new vdev
subdevice can continue to inherit the DMA attributes from the remoteproc's
parent device (actual platform device).

Cc: stable@vger.kernel.org
Fixes: 086d087 ("remoteproc: create vdev subdevice with specific dma memory pool")
Signed-off-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Link: https://lore.kernel.org/r/20200420160600.10467-3-s-anna@ti.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/remoteproc_core.c

@@ -517,7 +517,7 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
 
 	/* Initialise vdev subdevice */
 	snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
-	rvdev->dev.parent = rproc->dev.parent;
+	rvdev->dev.parent = &rproc->dev;
 	rvdev->dev.dma_pfn_offset = rproc->dev.parent->dma_pfn_offset;
 	rvdev->dev.release = rproc_rvdev_release;
 	dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);