[media] media: use macros to check for V4L2 subdev entities

Instead of relying on media subtype, use the new macros to detect
if an entity is a subdev or an A/V DMA entity.

Please note that most drivers assume that there's just AV_DMA or
V4L2 subdevs. This is not true anymore, as we've added MC support
for DVB, and there are plans to add support for ALSA and FB/DRM
too.

Ok, on the current pipelines supported by those drivers, just V4L
stuff are there, but, assuming that some day a pipeline that also
works with other subsystems will ever added, it is better to add
explicit checks for the AV_DMA stuff.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/platform/exynos4-is/fimc-isp-video.c

@@ -466,8 +466,7 @@ static int isp_video_pipeline_validate(struct fimc_isp *isp)
 
 		/* Retrieve format at the source pad */
 		pad = media_entity_remote_pad(pad);
-		if (pad == NULL ||
-		    media_entity_type(pad->entity) != MEDIA_ENT_T_V4L2_SUBDEV)
+		if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
 			break;
 
 		sd = media_entity_to_v4l2_subdev(pad->entity);