media: imx: imx7-media-csi: Drop unneeded src_sd check

The .s_stream() and .link_validate() operations can't be called with a
NULL src_sd, as subdev nodes are not registered before the async
notifier completes. Remove the unneeded checks.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Adam Ford <aford173@gmail.com> #imx8mm-beacon-kit
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Tested-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/platform/nxp/imx7-media-csi.c

@@ -1731,11 +1731,6 @@ static int imx7_csi_s_stream(struct v4l2_subdev *sd, int enable)
 
 	mutex_lock(&csi->lock);
 
-	if (!csi->src_sd) {
-		ret = -EPIPE;
-		goto out_unlock;
-	}
-
 	if (enable) {
 		ret = imx7_csi_init(csi);
 		if (ret < 0)
@@ -2026,9 +2021,6 @@ static int imx7_csi_pad_link_validate(struct v4l2_subdev *sd,
 	unsigned int i;
 	int ret;
 
-	if (!csi->src_sd)
-		return -EPIPE;
-
 	/*
 	 * Validate the source link, and record whether the source uses the
 	 * parallel input or the CSI-2 receiver.