V4L/DVB (7045): xc5000: Small amount of cleanup and commenting

xc5000: Small amount of cleanup and commenting, just for clarification.

Signed-off-by: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/dvb/frontends/xc5000.h b/drivers/media/dvb/frontends/xc5000.h
index 85b2d43..e0e8456 100644
--- a/drivers/media/dvb/frontends/xc5000.h
+++ b/drivers/media/dvb/frontends/xc5000.h
@@ -30,8 +30,16 @@
 struct xc5000_config {
 	u8   i2c_address;
 	u32  if_khz;
-	void *video_dev;
-	int  (*tuner_callback) (void *dev, int command, int arg);
+
+	/* For each bridge framework, when it attaches either analog or digital,
+	 * it has to store a reference back to its _core equivalent structure,
+	 * so that it can service the hardware by steering gpio's etc.
+	 * Each bridge implementation is different so cast priv accordingly.
+	 * The xc5000 driver cares not for this value, other than ensuring
+	 * it's passed back to a bridge during tuner_callback().
+	 */
+	void *priv;
+	int  (*tuner_callback) (void *priv, int command, int arg);
 };
 
 /* xc5000 callback command */