[media] cx25840: better document the media pads

Use an enum to better document the media pads.

No functional changes.
Suggested-by: Prabhakar Lad <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/i2c/cx25840/cx25840-core.c

@@ -5196,9 +5196,9 @@ static int cx25840_probe(struct i2c_client *client,
 	 * However, at least for now, there's no much gain on modelling
 	 * those extra inputs. So, let's add it only when needed.
 	 */
-	state->pads[0].flags = MEDIA_PAD_FL_SINK;	/* Tuner or input */
-	state->pads[1].flags = MEDIA_PAD_FL_SOURCE;	/* Video */
-	state->pads[2].flags = MEDIA_PAD_FL_SOURCE;	/* VBI */
+	state->pads[CX25840_PAD_INPUT].flags = MEDIA_PAD_FL_SINK;
+	state->pads[CX25840_PAD_VID_OUT].flags = MEDIA_PAD_FL_SOURCE;
+	state->pads[CX25840_PAD_VBI_OUT].flags = MEDIA_PAD_FL_SOURCE;
 	sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV_DECODER;
 
 	ret = media_entity_init(&sd->entity, ARRAY_SIZE(state->pads),

drivers/media/i2c/cx25840/cx25840-core.h

@@ -41,6 +41,14 @@ enum cx25840_model {
 	CX25837,
 };
 
+enum cx25840_media_pads {
+	CX25840_PAD_INPUT,
+	CX25840_PAD_VID_OUT,
+	CX25840_PAD_VBI_OUT,
+
+	CX25840_NUM_PADS
+};
+
 struct cx25840_state {
 	struct i2c_client *c;
 	struct v4l2_subdev sd;
@@ -65,7 +73,7 @@ struct cx25840_state {
 	struct work_struct fw_work;   /* work entry for fw load */
 	struct cx25840_ir_state *ir_state;
 #if defined(CONFIG_MEDIA_CONTROLLER)
-	struct media_pad	pads[3];
+	struct media_pad	pads[CX25840_NUM_PADS];
 #endif
 };