staging: bcm2835-camera: Remove/amend some obsolete comments

Remove a todo which has been done.
Remove a template line that was redundant.
Make a comment clearer as to the non-obvious meaning of a field.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>

drivers/staging/vc04_services/bcm2835-camera/controls.c

@@ -965,22 +965,13 @@ static const struct bm2835_mmal_v4l2_ctrl v4l2_ctrls[V4L2_CTRL_COUNT] = {
 		&ctrl_set_value,
 		false
 	},
-/*	{
- *		0, MMAL_CONTROL_TYPE_CLUSTER, 3, 1, 0, NULL, 0, NULL
- *	},
- */
 	{
 		V4L2_CID_EXPOSURE_AUTO, MMAL_CONTROL_TYPE_STD_MENU,
 		~0x03, V4L2_EXPOSURE_APERTURE_PRIORITY, V4L2_EXPOSURE_AUTO, 0,
 		NULL, MMAL_PARAMETER_EXPOSURE_MODE,
 		&ctrl_set_exposure,
 		false
 	},
-/* todo this needs mixing in with set exposure
- *	{
- *		V4L2_CID_SCENE_MODE, MMAL_CONTROL_TYPE_STD_MENU,
- *	},
- */
 	{
 		V4L2_CID_EXPOSURE_ABSOLUTE, MMAL_CONTROL_TYPE_STD,
 		/* Units of 100usecs */
@@ -1146,7 +1137,7 @@ static const struct bm2835_mmal_v4l2_ctrl v4l2_ctrls[V4L2_CTRL_COUNT] = {
 	},
 	{
 		V4L2_CID_SCENE_MODE, MMAL_CONTROL_TYPE_STD_MENU,
-		-1,	/* Min is computed at runtime */
+		-1,	/* Min (mask) is computed at runtime */
 		V4L2_SCENE_MODE_TEXT,
 		V4L2_SCENE_MODE_NONE, 1, NULL,
 		MMAL_PARAMETER_PROFILE,