[media] V4L: sh_mobile_csi2: fix unbalanced pm_runtime_put()

If the sh_mobile_csi2 driver didn't attach to a client, normally, because
the respective device connects to the SoC over the parallel CEU interface
and doesn't use the CSI-2 controller, it also shouldn't call
pm_runtime_put() on attempted disconnect.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/sh_mobile_csi2.c

@@ -208,6 +208,9 @@ static int sh_csi2_client_connect(struct sh_csi2 *priv)
 	unsigned long common_flags, csi2_flags;
 	int i, ret;
 
+	if (priv->client)
+		return -EBUSY;
+
 	for (i = 0; i < pdata->num_clients; i++)
 		if (&pdata->clients[i].pdev->dev == icd->pdev)
 			break;
@@ -262,6 +265,9 @@ static int sh_csi2_client_connect(struct sh_csi2 *priv)
 
 static void sh_csi2_client_disconnect(struct sh_csi2 *priv)
 {
+	if (!priv->client)
+		return;
+
 	priv->client = NULL;
 
 	pm_runtime_put(v4l2_get_subdevdata(&priv->subdev));