[media] em28xx: add support for Terratec Grabby REC button

Terratec Grabby (hw rev 2) REC button uses the standard snapshot button
configuration.

Signed-off-by: Matthieu Rogez <matthieu.rogez@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index 1f4047b..4051146 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -2015,6 +2015,7 @@
 			.vmux     = SAA7115_SVIDEO3,
 			.amux     = EM28XX_AMUX_LINE_IN,
 		} },
+		.buttons         = std_snapshot_button,
 	},
 	[EM2860_BOARD_TERRATEC_AV350] = {
 		.name            = "Terratec AV350",