V4L/DVB (12740): em28xx: better describe vinctrl registers

Properly document the video input control register, in preparation for the
addition of VBI support.  Note this patch makes no functional changes.

Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c
index 7e3c782..cc80723 100644
--- a/drivers/media/video/em28xx/em28xx-cards.c
+++ b/drivers/media/video/em28xx/em28xx-cards.c
@@ -2570,7 +2570,8 @@
 	 * Default format, used for tvp5150 or saa711x output formats
 	 */
 	dev->vinmode = 0x10;
-	dev->vinctl  = 0x11;
+	dev->vinctl  = EM28XX_VINCTRL_INTERLACED |
+		       EM28XX_VINCTRL_CCIR656_ENABLE;
 
 	/* Do board specific init and eeprom reading */
 	em28xx_card_setup(dev);