[media] ov7670: fix QVGA visible area

The QVGA mode has a green horizontal line on the left hand side, and a red
(or sometimes blue) vertical line at the bottom. Tweak the visible area
to remove them.

Thanks to Mauro for explaining how to fix this.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/ov7670.c

@@ -675,10 +675,10 @@ static struct ov7670_win_size {
 		.width		= QVGA_WIDTH,
 		.height		= QVGA_HEIGHT,
 		.com7_bit	= COM7_FMT_QVGA,
-		.hstart		= 164,		/* Empirically determined */
-		.hstop		=  20,
-		.vstart		=  14,
-		.vstop		= 494,
+		.hstart		= 168,		/* Empirically determined */
+		.hstop		=  24,
+		.vstart		=  12,
+		.vstop		= 492,
 		.regs 		= NULL,
 	},
 	/* QCIF */