[media] media: change pipeline validation return error

According to the V4L2 API, the VIDIOC_STREAMON ioctl should return EPIPE
if there is a format mismatch in the pipeline configuration.

As the .vidioc_streamon in the v4l2_ioctl_ops usually forwards the error
caused by the v4l2_subdev_link_validate_default (if it is in use), it
should return -EPIPE when it detect the mismatch.

When an entity is connected to a non enabled link,
media_entity_pipeline_start should return -ENOLINK, as the link does not
exist.

Signed-off-by: Helen Mae Koike Fornazier <helen.koike@collabora.co.uk>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 224ea60..953eab0 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -510,7 +510,7 @@
 	if (source_fmt->format.width != sink_fmt->format.width
 	    || source_fmt->format.height != sink_fmt->format.height
 	    || source_fmt->format.code != sink_fmt->format.code)
-		return -EINVAL;
+		return -EPIPE;
 
 	/* The field order must match, or the sink field order must be NONE
 	 * to support interlaced hardware connected to bridges that support
@@ -518,7 +518,7 @@
 	 */
 	if (source_fmt->format.field != sink_fmt->format.field &&
 	    sink_fmt->format.field != V4L2_FIELD_NONE)
-		return -EINVAL;
+		return -EPIPE;
 
 	return 0;
 }